kec

1. (in cards) ace
   Imam keca i kralja u ruci. — I have an ace and a king in my hand.
   Izvukao je keca pik. — He drew the ace of spades.
2. colloq. (at school) a one; failing grade
   Dobio sam keca iz hemije. — I got a one in chemistry.
   Ako dobiješ još jednog keca, pašćeš razred. — If you get one more failing grade, you'll have to repeat the year.
3. colloq. the number one
   Opet sam bacio keca na kocki. — I rolled a one on the dice again.

In the accusative the form keca is usually used: dobiti keca.