upad

1. incursion; raid; intrusion
   Policija je izvršila upad u stan osumnjičenog. — The police raided the suspect's flat.
   Vojska je sprečila upad neprijatelja preko granice. — The army prevented an enemy incursion across the border.
2. (in conversation) interruption; interjected remark
   Izvinite na upadu, ali moram nešto da dodam. — Sorry to butt in, but I have to add something.
3. colloq. barging in; unannounced visit
   Oprosti na upadu, samo sam svratio po ključeve. — Sorry for barging in, I just stopped by for the keys.

Usually used with u + acc.: upad u stan, upad u kazneni prostor.