The verb znati, simply means to know or to be informed. It’s a regular verb that belongs to the A group. But when it’s connected to another verb with the conjunction da, it means to know how, to have to ability or skill of doing something. In this meaning, it has a synonym: umeti. So both umeti and znati are used to tell that we have the ability or skill for doing something.
Umeti is the root for the words umetnost (art) and umeće (know-how, skill).
|to know, to be informed||znati||Ana dobro zna istoriju. Ana knows history well.
Ana zna engleski. Ana knows (can speak) English.
|to know how, to have ability or skill||umeti, znati||Ana ume/zna da pliva. Ana can (knows how to) swim.
Dete ume/zna da vozi bicikl. The child can ride a bike.
Smeti has several meanings: to be allowed, can, may or dare. But when negated, it’s used to express forbiddance, must not. So: to say must, we use the verb morati, and for mustn’t we use ne smeti.
|be allowed, can, dare||smeti||Dete sme da ide napolje posle ručka. The child is allowed to go outside after lunch.
Smem li da pitam nešto? Can I ask something?
Niko to ne sme da kaže. No one dares to say that.
|forbiddance (must not)||ne smeti||Ne smeš da pušiš u biblioteci. You mustn’t smoke at the library.
Dijabetičari ne smeju da jedu šećer. Diabetics mustn’t eat sugar.
Umeti, razumeti i smeti are three special verbs that belong to the E group of verbs, but in the third person plural they have this infix: -ej-. So instead of the ending –u as we expect in the E conjugation, we use –eju: oni umeju, oni razumeju, oni smeju.
Because of this ending, they look like a combination of the E and A verbal groups!
Razumeti (to understand) is actually a verb compound from the verb umeti with the prefix raz-.