French builds most comparatives the regular way: plus / moins / aussi + adjective + que — plus grand que, moins intelligent que, aussi heureux que. But four high-frequency adjective and adverb pairs refuse the regular pattern and impose irregular forms. Bon does not become plus bon — it becomes meilleur. Mauvais and petit have alternative irregular forms (pire, moindre) that compete with the regular plus mauvais and plus petit in different registers and meanings. The adverbs bien and mal also have their own irregular comparatives (mieux, plus mal) that learners reliably confuse with the adjective forms. Together these four sets cover the most-used comparison vocabulary in everyday French — and the most error-prone area for English speakers, who can default to a regular plus + adjective and sound wrong every time.
This page drills the irregular forms in detail: when each is required, when an alternative is allowed, what register signal each carries, and the points where intermediate learners reliably go wrong.
The headline rule: never plus bon
The single most important point on this page: do not say plus bon. The comparative of bon is meilleur. Always.
Ce gâteau est meilleur que celui d'hier.
This cake is better than yesterday's.
Le café est meilleur en Italie.
The coffee is better in Italy.
C'est une meilleure idée que la première.
It's a better idea than the first one.
Meilleur is the comparative; it agrees with the noun like any adjective: meilleur (m.), meilleure (f.), meilleurs (m.pl.), meilleures (f.pl.). To make it a superlative, prefix the definite article: le meilleur, la meilleure, les meilleurs, les meilleures.
C'est le meilleur livre que j'aie lu cette année.
It's the best book I've read this year.
Voici la meilleure boulangerie du quartier.
This is the best bakery in the neighbourhood.
Les meilleures vacances que j'aie passées.
The best holidays I've ever had.
The English equivalent works exactly the same way: good → better → best. The structure is parallel; only the French insistence on meilleur (never plus bon) is unfamiliar.
The one place plus + bon is possible is when bon means something other than the standard "good" — for instance, in informal speech where bon takes on the sense of kind: Il n'est pas plus bon avec moi qu'avec les autres (He's not any nicer to me than to anyone else). But this is marginal and you can ignore it. In ninety-nine cases out of a hundred, plus bon is wrong; use meilleur.
Mauvais → pire (and plus mauvais)
The comparative and superlative of mauvais (bad) have two competing forms: a regular one (plus mauvais) and an irregular one (pire). Both are correct, but they tilt to different registers and meanings.
C'est pire que je ne pensais.
It's worse than I thought.
Le chômage est pire qu'il y a dix ans.
Unemployment is worse than ten years ago.
C'est plus mauvais cette année que l'année dernière.
It's worse this year than last year.
The split:
- Pire — used for abstract or moral evil, intensification, and the most emphatic register. Pire is what you reach for in formal or written French and in moments of strong emotion.
- Plus mauvais — used for concrete quality judgments, especially when the badness is of a measurable kind: a bad wine, a bad film, a bad student. Frequent in spoken French.
In practice, the two overlap heavily and either is usually understood. The leaning matters more in writing than in speech.
Cette année, le vin est plus mauvais que l'année dernière.
This year, the wine is worse than last year. (concrete quality)
Sa situation est pire que la mienne.
His situation is worse than mine. (abstract gravity)
The superlative follows the same logic: le pire (the worst — most often used) and le plus mauvais (less common but possible).
C'était le pire jour de ma vie.
It was the worst day of my life.
C'est le pire film que j'aie jamais vu.
It's the worst film I've ever seen.
C'est le plus mauvais élève de la classe.
He's the worst student in the class.
Pire is invariable in gender (one form for masc. and fem.) but takes -s in the plural: les pires moments. Plus mauvais takes the regular four-form agreement: plus mauvais, plus mauvaise, plus mauvais, plus mauvaises.
Petit → moindre (and plus petit)
Petit (small) is the third irregular adjective, and the split is the cleanest of all three. The two forms have different meanings.
- Plus petit — smaller in physical size.
- Moindre — lesser in importance, abstract degree.
Mon appartement est plus petit que le tien.
My flat is smaller than yours. (physical size)
Cette boîte est plus petite que celle-là.
This box is smaller than that one.
C'est un moindre mal.
It's a lesser evil.
Sans le moindre doute, oui.
Without the slightest doubt, yes.
Moindre is (formal/literary); in everyday speech it appears mostly in fixed expressions and rhetorical formulas. The most common are:
- un moindre mal — a lesser evil
- au moindre bruit — at the slightest sound
- sans le moindre doute — without the slightest doubt
- le moindre détail — the slightest detail
- je n'en ai pas la moindre idée — I haven't the slightest idea
Au moindre problème, appelle-moi.
At the slightest problem, call me.
Je n'en ai pas la moindre idée.
I haven't the slightest idea.
Elle remarque le moindre détail.
She notices every smallest detail.
The superlative le moindre / la moindre / les moindres is much more common than the comparative moindre que. Native speakers reach for le moindre in fixed expressions and reach for plus petit for everything physical.
C'est le plus petit chien que j'aie jamais vu.
It's the smallest dog I've ever seen. (physical)
Au moindre risque, on annule.
At the slightest risk, we cancel. (abstract)
A learner-friendly rule of thumb: if you can point at the thing and measure it with a ruler, use plus petit. If it is an idea, a feeling, a probability, a doubt — moindre.
The adverbs: bien → mieux, mal → plus mal (or pire)
The irregular comparison story does not stop with adjectives. The adverbs bien (well) and mal (badly) have their own irregular comparative forms, which learners constantly confuse with the adjectival ones.
- bien (well) → mieux (better) → le mieux (the best)
- mal (badly) → plus mal OR pire (worse) → le plus mal / le pire (the worst)
Elle parle français mieux que moi.
She speaks French better than me.
Je dors mieux depuis que j'ai changé de matelas.
I sleep better since I changed mattress.
C'est lui qui chante le mieux.
He's the one who sings best.
Aujourd'hui je vais plus mal qu'hier.
Today I feel worse than yesterday.
Il joue plus mal que son frère.
He plays worse than his brother.
The killer point: mieux is the adverb (modifies a verb); meilleur is the adjective (modifies a noun). They mean the same thing — "better" — but they sit in different syntactic slots.
Ce gâteau est meilleur.
This cake is better. (adjective — describes the cake)
Ce gâteau cuit mieux dans ce four.
This cake bakes better in this oven. (adverb — describes how it bakes)
The English better covers both functions, which is exactly why English speakers mix them up in French. A clean test: if the word is sitting beside être, paraître, sembler, or another linking verb, or describing a noun, use meilleur. If it is modifying a verb of action, use mieux.
Elle est meilleure en mathématiques que son frère.
She is better at maths than her brother. (adjective with être)
Elle comprend mieux les mathématiques que son frère.
She understands maths better than her brother. (adverb with comprend)
Adjectives that DO take plus — the regular majority
So that the irregular set does not loom larger than it deserves: the vast majority of French adjectives take the regular plus / moins / aussi + adjective + que construction. There is no "watch-out" mental list to memorize beyond the four irregulars above.
Mon frère est plus grand que moi.
My brother is taller than me.
Elle est plus heureuse depuis son mariage.
She's happier since her wedding.
Ce film est plus intelligent que je ne l'aurais cru.
This film is smarter than I would have thought.
C'est aussi cher que là-bas.
It's as expensive as over there.
Elle est moins fatiguée aujourd'hui.
She's less tired today.
The adjectives grand, petit (in size), heureux, intelligent, fatigué, cher, important, intéressant, fort, facile, difficile, jeune, vieux, beau, content, triste, gentil, méchant, froid, chaud — all regular. Plus grand que, plus heureux que, plus intelligent que, plus beau que. No tricks.
The irregular set is exactly: bon, mauvais, petit (abstract), bien, mal. That's it. Memorize those five and the regular pattern handles everything else.
A consolidated reference table
| Base form | Comparative | Superlative | Notes |
|---|---|---|---|
| bon (good) | meilleur | le meilleur | Never plus bon. Full agreement. |
| mauvais (bad) | pire OR plus mauvais | le pire / le plus mauvais | Pire = abstract; plus mauvais = concrete. |
| petit (small) | plus petit (physical) / moindre (abstract) | le plus petit / le moindre | Moindre is formal/literary. |
| bien (well, adv.) | mieux | le mieux | Adverb. Invariable. |
| mal (badly, adv.) | plus mal OR pire | le plus mal / le pire | Adverb. Invariable. |
| grand, intelligent, etc. | plus + adj + que | le plus + adj | Regular. Adj agrees normally. |
Register and frequency notes
- Meilleur — neutral; the only standard form for "better" applied to a noun. Required.
- Pire — slightly more emphatic; common in writing and emotional speech. Default for abstract badness.
- Plus mauvais — neutral; common in spoken French for measurable quality. Default for concrete badness.
- Moindre — (formal/literary); in spoken French only in fixed expressions.
- Plus petit — neutral; the everyday word for "smaller."
- Mieux — neutral; the only standard adverb form for "better."
A native speaker will reach for meilleur over plus bon without thinking. The same speaker will use plus mauvais for a meal and pire for a tragedy, sometimes both in the same conversation, with no felt inconsistency.
Common mistakes
❌ Ce vin est plus bon que l'autre.
Incorrect — *plus bon* does not exist; the comparative of *bon* is *meilleur*
✅ Ce vin est meilleur que l'autre.
This wine is better than the other one.
❌ Elle parle français meilleur que moi.
Incorrect — *meilleur* is an adjective; *better* with a verb of action is *mieux*
✅ Elle parle français mieux que moi.
She speaks French better than me.
❌ Ce gâteau est mieux que l'autre.
Incorrect — to say the cake itself is better, use the adjective meilleur, not the adverb mieux
✅ Ce gâteau est meilleur que l'autre.
This cake is better than the other one.
❌ Au plus petit problème, appelle-moi.
Awkward — the fixed idiomatic expression uses moindre
✅ Au moindre problème, appelle-moi.
At the slightest problem, call me.
❌ C'est le plus bon film de l'année.
Incorrect — superlative of *bon* is *le meilleur*
✅ C'est le meilleur film de l'année.
It's the best film of the year.
❌ Elle est mieux en maths que moi.
Incorrect — with *être* + ability, use the adjective *meilleure*
✅ Elle est meilleure en maths que moi.
She is better at maths than me.
The plus bon error is so deeply automatic for English speakers that it persists into B2. Force yourself to say meilleur even when plus bon feels more rule-driven. The mieux / meilleur mix-up is the next most stubborn — train the est-meilleur, comprend-mieux test until it fires automatically.
Key takeaways
- Bon → meilleur → le meilleur. Always. Never plus bon. The adjective agrees normally.
- Mauvais → pire (abstract) OR plus mauvais (concrete) → le pire / le plus mauvais. Pire is more emphatic.
- Petit → plus petit (size) OR moindre (abstract) → le plus petit / le moindre. Moindre is formal/fixed.
- Bien (adverb) → mieux → le mieux. Mal (adverb) → plus mal / pire → le pire / le plus mal.
- The killer test for meilleur vs mieux: meilleur with être and nouns; mieux with action verbs. Memorize est-meilleur, comprend-mieux.
- The vast majority of adjectives take regular plus + adj + que. The four irregular sets above are the only exceptions you need to memorize.
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Start learning French→Related Topics
- Les Adjectifs en Français: OverviewA1 — How French adjectives work — the four-form agreement system, the after-the-noun default position, the small set that goes before, and the irregular forms every learner needs from day one.
- Phrases ComparativesB1 — Building comparative sentences in French — the plus/moins/aussi system for adjectives, adverbs, nouns, and verbs, the irregular comparatives meilleur, mieux, and pire, and the obligatory disjunctive pronoun after que.
- Phrases SuperlativesB2 — Building superlative sentences in French — the le plus / le moins pattern, agreement of the article with the noun, the position of the adjective, the obligatory subjonctif after a superlative, and the irregular forms le meilleur, le pire, le mieux.
- Les Subordonnées Comparatives: Plus que, Aussi que, Plus...plusB1 — Comparison clauses pin one thing against another along some scale: taller, smarter, as fast, less expensive. French handles inequality with plus/moins...que, equality with aussi/autant...que, and proportional change with the elegant plus...plus / moins...moins construction. The ne explétif and the meilleur/mieux split round out a system that English tackles much more loosely.
- Le Superlatif: Le plus, Le moins, et le SubjonctifB2 — The superlative singles out one item as the extreme of its group: the biggest, the least expensive, the best book I've ever read. French builds the superlative with le/la/les + plus or moins, agrees the article and adjective for gender and number, and triggers the subjunctive in relative clauses that follow. The irregular meilleur, pire, and mieux complete the picture.