Osobine

Serbian adjectives agree with the noun they describe. In practice that means you almost never learn an adjective as one word — you learn a small set of endings and then choose.

Two rows in that table cause nearly all the mistakes. Srednji rod množine ends in -a, which looks exactly like feminine singular and is not: optimistična deca, not optimistične. And deca makes it worse, because the word itself looks singular and feminine. It is neuter plural, and everything around it has to agree that way.

The other trap is -i versus -e in the plural. Masculine takes -i, feminine takes -e: strogi šefovi but stroge šefice. If a group is mixed, Serbian defaults to the masculine.

The vocabulary here is all about character. Notice how transparent most of it is once you see the parts: dobro + nameran = well-intentioned, zlo + nameran = ill-intentioned, dvo + ličan = two-faced, ne + ustrašiv = fearless. Serbian builds these in the open, so a word you have never met is often one you can still take apart.