gamad

1. vermin
   Stara kuća je bila puna gamadi. — The old house was full of vermin.
   Moramo da očistimo podrum od gamadi. — We have to get rid of the vermin in the basement.
2. derog. (of people) scum
   Ti prevaranti su obična gamad. — Those crooks are nothing but scum.

A collective noun: attributive modifiers are singular; the predicate can take singular or plural agreement.