vređati

1. (+ acc.) to insult; to offend
   Stalno vređa kolege na poslu. — He keeps insulting his colleagues at work.
   Ovakva reklama vređa inteligenciju gledalaca. — An ad like this insults viewers' intelligence.
2. (vređati se) to insult each other
   Komšije su se vređale preko ograde. — The neighbours were insulting each other over the fence.
3. (vređati se) to take offence; to be offended
   Nemoj da se vređaš, samo se šalim. — Don't take offence, I'm only joking.

The perfective is uvrediti; 'to take offence' is uvrediti se.