Adjectives with a bare case complement

English glues these little phrases together with a preposition: full of water, satisfied with the pay, hungry for attention. Serbian usually uses nothing at all. The adjective simply puts the noun after it into a case, and that case does all the joining: Čaša je puna vode. — "The glass is full of water", literally "the glass is full water's".

Which case? That depends on the adjective, not on the meaning. Most of these adjectives take the genitive; a smaller, very common group takes the instrumental. So you learn one of these adjectives together with its case, the same way you learn a verb together with the case of its object.

The genitive group

These put their complement in the genitive — the same case you already use after bez, after od and after mnogo.

gladan and sit are also the ordinary everyday words for hungry and full up, with nothing after them: Gladan sam. "I'm hungry." Sit sam. "I've had enough to eat." Put a genitive after them and the meaning turns figurative: Gladan sam pažnje. "I'm starved of attention."

prazan / prazna (empty) is the opposite of pun, but it takes no complement at all. You say Flaša je prazna. and stop there — there is no Serbian way to say "empty of" with this adjective.

The instrumental group

A short list, but you will use it constantly. These put their complement in the instrumental — the case you know from s(a) “with”, only here with no s(a) in front of it.

Singular or plural — the case stays

The complement is an ordinary noun phrase, so it can just as well be plural. Nothing about the construction changes: the adjective still fixes the case, and only the number of the noun moves.

Two agreements, and they answer to different masters

Two things happen in the same short sentence, and it is easy to let one drag the other. The adjective agrees with the subject in gender and number, exactly as an adjective always does — pun / puna / puni / pune, sit / sita / siti, zadovoljan / zadovoljna / zadovoljni / zadovoljne. The complement takes the case its adjective fixes, and that case never moves, whoever the subject is.

A plural subject changes the adjective and nothing else: Kutije su pune knjiga. "The boxes are full of books." Oni su siti obaveza. "They are fed up with obligations." The complement is genitive in both, exactly as it was in the singular.

The trap is choosing the case from the English preposition. "Full of" and "satisfied with" feel like different relations in English, but in Serbian both are simply adjective + bare case, and which case it is is a fact about the Serbian word. pun takes the genitive, zadovoljan takes the instrumental, and no amount of thinking about the meaning will tell you which.

You will also hear a preposition

In speech you will meet Čaša je puna od vode and Zadovoljan sam sa platom. Notice what does not change: the noun is still genitive after pun and still instrumental after zadovoljan. The preposition is an optional extra some speakers add — the bare version is the standard one, and the one to write.