Ability and Permission: moći, smjeti, znati | Croatian Grammar

English packs three quite different ideas into one little word, "can": being able to do something, being allowed to do it, and knowing how to do it. Croatian keeps them apart with three separate verbs — moći (ability and possibility), smjeti (permission), and znati (acquired skill). Choosing the wrong one produces sentences that are grammatical but mean something you did not intend, and two of those mistakes are practically guaranteed for English speakers: saying mogu plivati ("I'm able to swim right now") when you mean "I know how to swim" (znam plivati), and saying ne možeš ("you're unable") when you mean "you're not allowed" (ne smiješ). This page draws the three lines clearly.

moći: ability and possibility ("can / be able to")

Moći is "can" in the sense of being physically or circumstantially able, and more broadly "it is possible." It takes an infinitive. Note the consonant alternation in its stem (the č/ž of moć-/mož-/mog-).

Person	moći (present)
ja	mogu
ti	možeš
on/ona/ono	može
mi	možemo
vi	možete
oni/one/ona	mogu

(The 1st-person singular and 3rd-person plural are identical: mogu. Context and any pronoun sort them out.)

Mogu ti pomoći sutra ujutro.

I can help you tomorrow morning.

Ne mogu otvoriti ovu teglu, prečvrsto je zatvorena.

I can't open this jar, it's screwed on too tight.

Možeš li govoriti malo sporije?

Can you speak a little more slowly?

Moći also handles impersonal "is it possible," typically with the reflexive se, and produces two of the most useful conversational words in the language: Može? ("OK? / all right?") and Može! ("Sure! / OK!").

Može li se ovdje platiti karticom?

Can one pay by card here? / Is paying by card possible here?

Idemo na kavu? — Može!

Shall we get a coffee? — Sure!

Vidimo se u osam, može?

See you at eight, OK?

smjeti: permission ("be allowed to / may")

Smjeti is "can" in the sense of being permitted. This is the verb for asking and granting permission, and for stating what is forbidden.

Person	smjeti (present)
ja	smijem
ti	smiješ
on/ona/ono	smije
mi	smijemo
vi	smijete
oni/one/ona	smiju

Smijem li ući?

May I come in?

Smiješ ostati koliko god želiš.

You're allowed to stay as long as you like.

Smije li dijete jesti slatkiše prije ručka?

Is the child allowed to eat sweets before lunch?

The negative ne smjeti is the true equivalent of English "must not / mustn't" — a prohibition, not a statement of inability.

Ne smiješ pušiti u zatvorenom prostoru.

You mustn't / aren't allowed to smoke indoors.

Djeca ne smiju sama prelaziti cestu.

Children mustn't cross the road on their own.

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The killer contrast: ne mogu = "I can't" (I'm unable); ne smijem = "I mustn't" (I'm not allowed). "You can't smoke here" almost always means Ne smiješ pušiti ovdje (forbidden), not Ne možeš (which would absurdly claim you're physically incapable of smoking). When a rule, a sign, or an authority is behind the "can't," reach for smjeti.

znati: acquired skill ("know how to")

Znati means "to know," and one of its core uses is "to know how to" — a skill you have learned and retain: swimming, driving, a language, an instrument. English says "I can swim," but the claim is about knowing how, not about present ability, so Croatian uses znati + infinitive.

Person	znati (present)
ja	znam
ti	znaš
on/ona/ono	zna
mi	znamo
vi	znate
oni/one/ona	znaju

Znam plivati otkad sam bila mala.

I've known how to swim since I was little. (female speaker)

Znaš li voziti motor?

Do you know how to ride a motorbike? / Can you ride a motorbike?

Ne znam kuhati, ali učim.

I can't cook (don't know how), but I'm learning.

The difference between moći and znati here is real, not pedantic. Znam plivati says "I have the swimming skill." Mogu plivati says "I am able to swim in this situation right now" — for instance, the pool is open, my leg has healed, nothing is stopping me. Mixing them up changes the meaning.

Znam plivati, ali danas ne mogu jer me boli rame.

I know how to swim, but today I can't because my shoulder hurts.

This one sentence holds the whole system: znam (the skill is permanent) versus ne mogu (today's circumstances block it). For more on the znati / poznavati / umjeti family of "knowing," see Knowing: znati, poznavati, umjeti.

Putting all three together

The cleanest way to feel the three-way split is to watch them in one breath, each negative carrying a distinct meaning:

Znam plivati, ali danas ne smijem u vodu jer sam prehlađen, pa ipak ne mogu s vama na bazen.

I know how to swim, but today I'm not allowed in the water because I have a cold, so I can't come to the pool with you after all.

Here znam states the skill, ne smijem the prohibition (doctor's orders), and ne mogu the resulting impossibility. English would say "can" or "can't" in all three slots; Croatian forces — and rewards — the distinction.

English "can / can't"	Croatian verb	Meaning	Example
be able to (right now)	moći	ability / possibility	Mogu ti pomoći.
be allowed to	smjeti	permission	Smijem li ući?
know how to	znati	acquired skill	Znam plivati.
can't (unable)	ne moći	inability	Ne mogu doći.
mustn't (forbidden)	ne smjeti	prohibition	Ne smiješ ovdje.
can't (no skill)	ne znati	lack of skill	Ne znam kuhati.

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A quick self-test before you say "can": is it about my capacity in the moment (moći), about permission (smjeti), or about a learned skill (znati)? "Can you pass the salt?" → moći (you're able to). "Can I sit here?" → smjeti (am I allowed?). "Can you play piano?" → znati (have you the skill?).

Common Mistakes

❌ Mogu plivati od djetinjstva.

Wrong sense — this claims present ability, not the lifelong skill.

✅ Znam plivati od djetinjstva.

I've known how to swim since childhood. — a learned skill uses 'znati'.

❌ Ne možeš ovdje parkirati.

Misleading — it says 'you're unable to park here', not that it's forbidden.

✅ Ne smiješ ovdje parkirati.

You mustn't park here. — a prohibition uses 'ne smjeti'.

❌ Smijem voziti, položio sam prošli tjedan.

Wrong if you mean the skill — 'smjeti' is permission, not know-how.

✅ Znam voziti, položio sam prošli tjedan.

I can drive, I passed last week. — having the skill uses 'znati'.

❌ Smijem li dobiti račun, molim?

Odd — asking for the bill isn't about permission; use 'moći'.

✅ Mogu li dobiti račun, molim?

Can I have the bill, please? — a request for possibility uses 'moći'.

Key Takeaways

moći = able / possible ("can right now"); also the conversational Može? / Može! ("OK?" / "Sure!").
smjeti = allowed ("may"); its negative ne smjeti is the true "mustn't / forbidden."
znati = know how to (a learned skill): Znam plivati, Znam voziti.
The two guaranteed English-speaker errors: using moći for a permanent skill (say znati), and using ne moći for a prohibition (say ne smjeti).
Znam plivati, ali danas ne mogu jer ne smijem u vodu — keep this sentence as your three-way reference.

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