Invariable Adjectives

Most Portuguese adjectives agree with their noun for both gender and number — four forms in total. But a meaningful group of adjectives is invariable: they use a single form regardless of what they modify. The key insight for learners is that "invariable" in Portuguese comes in degrees. Some adjectives are invariable only for gender (they still pluralise). Some are invariable only for number (rare). And a specific set — mostly colours derived from nouns, plus a few native adjectives — is invariable for both. Recognising which category an adjective belongs to is essential for writing correctly, and for not producing the all-too-common errors like *vestidos rosas instead of vestidos cor-de-rosa.

Invariable in gender only (the -e, -z, -l, -r, -m groups)

These adjectives have a single form for masculine and feminine, but they do pluralise following the regular rules covered in number agreement.

-e endings:

-z endings: feliz → felizes, capaz → capazes, feroz → ferozes, tenaz → tenazes, audaz → audazes, voraz → vorazes.

-l endings: fácil → fáceis, útil → úteis, amável → amáveis, difícil → difíceis, frágil → frágeis, agradável → agradáveis.

-r endings: maior → maiores, melhor → melhores, pior → piores, superior → superiores.

-m endings: comum → comuns, jovem → jovens, bom → bons.

Fully invariable adjectives

A smaller set does not change at all — same form for singular, plural, masculine, feminine. These are true exceptions that you must memorise.

Colour adjectives derived from nouns

This is where learners most often slip. When a Portuguese colour word comes from a noun — usually the name of the thing that has the colour — the word is invariable.

The logic here is transparent once you see it. Laranja originally means the fruit, and a dress is not "oranges" — it is "orange-coloured." The adjectival use is really shorthand for da cor de laranja ("the colour of an orange"). Since the colour reference point doesn't change with the number of dresses, the word doesn't either.

Compound colour phrases

The moment you combine two colours — or add a modifier like claro (light) or escuro (dark) — the whole compound becomes invariable.

Notice what does not happen: you do not say *dois fatos azuis-marinhos. The compound behaves as a single unit, and neither half inflects.

-ista, -ote, and other special endings

Adjectives ending in -ista (from profession/ideology noun roots) and -ote are invariable in gender but inflect normally in number.

Context matters: when "colour word" is really a noun

Some colour words are genuinely adjectives and genuinely nouns, and the behaviour depends on which role they're playing.

Rosa as a colour adjective is invariable: um vestido rosa, dois vestidos rosa. Rosa as a noun means "a rose" and pluralises normally: uma rosa, duas rosas.

Here rosas (the flowers) takes the plural ending; cor-de-rosa (the colour) does not. Both in one sentence — a classic Portuguese test.

The participle exception

Past participles used as adjectives do agree in full (they are not invariable) — cansado/cansada/cansados/cansadas, preocupado/-a/-os/-as. There's nothing special about them; we just flag it here because learners sometimes think "past participles are fixed forms" carried over from their verbal use. They aren't, once they become adjectives.

Common mistakes

Quick reference: is this adjective invariable?

See also: colour adjectives for the full tour of how Portuguese handles colour words.

Key takeaways

Invariable means different things: some adjectives don't change for gender (most consonant and -e endings), while a smaller set never changes at all (simples, grátis, plus colour nouns like laranja, cor-de-rosa, bege). Compound colours also lock — azul-marinho never pluralises. When in doubt, ask yourself: is this colour word originally a noun? If yes, it's probably invariable. Memorise the small list of fully invariable core adjectives (simples, grátis, reles) and you'll avoid most errors.