njušiti

1. (usually of animals) to sniff; to smell
   Pas njuši svaki žbun u parku. — The dog sniffs every bush in the park.
   Mačka je dugo njušila hranu. — The cat sniffed the food for a long time.
2. colloq. to sense; to scent
   Novinari već njuše veliki skandal. — Journalists can already smell a big scandal.

For "snooping around" njuškati is more common.