gunđalo

1. colloq. grumbler; grouch
   Moj deda je pravo gunđalo, ništa mu ne valja. — My grandpa is a real grouch, nothing is ever right for him.
   Ne budi takvo gunđalo, biće sve u redu. — Don't be such a grumbler, everything will be fine.

Used of both men and women; with a male referent, modifiers may be masculine (taj gunđalo).