Irregular Present-Tense Verbs

A handful of Croatian verbs refuse to fit the three regular present classes — and, by a law that holds across every language, they are precisely the verbs you use most. Biti ("to be"), htjeti ("to want / will"), ići ("to go") and moći ("can") are not only irregular, they also double as auxiliaries and modals: biti builds the past, htjeti builds the future, moći expresses possibility. You cannot make a single past or future sentence without them. So these are not optional advanced trivia — they are the load-bearing beams of the whole verb system, and the only sensible strategy is to memorise each one as a complete paradigm, early and cold.

biti — "to be"

Biti is doubly irregular: it has two present-tense sets. The clitic (short) form sam, si, je… is the everyday unstressed copula and the past-tense auxiliary. The full (stressed) form jesam, jesi, jest… is used for emphasis, for short affirmative answers, and after certain words. There is also the dedicated negative form nisam, nisi… (you never say ne sam).

The clitic forms cannot start a sentence or stand alone; the full forms can. "Are you tired?" — "Yes, I am." uses the full form for the answer: Jesi li umoran? — Jesam.

htjeti — "to want / will"

Htjeti is irregular and, like biti, has a stressed full form and an unstressed clitic form (the clitic builds the future tense). The full present means "want"; the clitic ću, ćeš… is the future auxiliary.

Note that neću, nećeš… is written as one word — the negative of htjeti is famously irregular in spelling (it is one of the very few cases where ne fuses with the verb instead of standing apart).

ići — "to go"

The present of ići is suppletive: the present stem id- has no visible connection to the infinitive ići. (Compare English go / went, where the past comes from a different root entirely.) The endings are the regular e-class set; only the stem is the surprise.

The same id- stem reappears in every prefixed compound: doći → dođem ("come"), otići → odem ("leave"), ući → uđem ("enter"), izaći → izađem ("go out"). Learn idem once and these all become reachable.

moći — "can / be able to"

Moći carries a consonant alternation straight out of the old Slavic sound system: the stem-final g surfaces as g in the 1sg and 3pl but mutates to ž everywhere else. Watch the mogu / možeš / mogu frame.

So the 1sg and 3pl are identical (mogu) and both keep the g; the four middle forms show ž (možeš, može, možemo, možete). This g ~ ž swap is the same first-palatalization that gives Bog → Bože. The single word Može! on its own is also the most common Croatian way to say "Okay! / Sure! / Sounds good."

jesti, dati, znati — three more to watch

Jesti ("to eat") has the present stem jed- with regular e-class endings: jedem, jedeš, jede, jedemo, jedete, jedu. The infinitive jesti hides the d that the present reveals.

Dati ("to give") is perfective, so its present does not mean "I give now" — it functions as a future/subordinate form (see Using the Present Tense). It has two living present stems: the common dam, daš, da, damo, date, daju and the older dadem / dadnem set (more formal or regional). Beginners should use dam, daš, da….

Znati ("to know") looks like it should be irregular but is in fact a plain -a- class verb: znam, znaš, zna, znamo, znate, znaju. It is listed here only because learners expect it to be tricky — it isn't. The same is true of spavati → spavam ("sleep") and imati → imam ("have"): regular -a- verbs hiding among the famous irregulars.

How this compares to English

English keeps almost no present-tense irregularity (am / is / are is essentially the only survivor). Croatian, like German or French, keeps a richer set, and crucially its irregular verbs are multi-functional: biti is both "to be" and the past-tense auxiliary; htjeti is both "to want" and the future marker; moći is both a full verb and a modal. That overloading is why these four repay early, total memorisation more than any other words in the language — every tense you build later runs through them.

Common Mistakes

Key Takeaways

• biti: clitic sam/si/je…, full jesam/jesi/jest…, negative nisam/nisi… — three sets, all essential.
• htjeti: full hoću ("want"), clitic ću (future), negative one-word neću.
• ići: suppletive present stem id- (idem), reused in dođem, odem, uđem.
• moći: mogu — možeš — mogu, with the g ~ ž alternation; Može! = "Okay!".
• znati, imati, spavati look scary but are regular -a- verbs.