zagrizati

1. (+ acc. or u + acc.) to bite into; to take a bite of
   Dete zagriza jabuku i smeje se. — The child bites into the apple and laughs.
   Kad god zagrizam nešto hladno, zaboli me zub. — Whenever I bite into something cold, my tooth hurts.
2. colloq. (u + acc.) to get stuck into; to tackle; to get into
   Tek sada ozbiljno zagriza u studije. — Only now is he really getting stuck into his studies.

For a single completed bite, the perfective zagristi is usually used.