delfin

1. dolphin
   Na letovanju smo videli delfine blizu obale. — On holiday we saw dolphins near the shore.
2. (in swimming) butterfly stroke
   Najteže mi je da plivam delfin. — Butterfly is the hardest stroke for me.
   Osvojio je zlato na sto metara delfin. — He won gold in the 100 metres butterfly.
3. colloq. (plural, water polo team) players of the Serbian national water polo team
   Delfini su ponovo osvojili olimpijsko zlato. — The Dolphins won Olympic gold again.

Sports labels can use the unchanged form delfin: sto metara delfin. The noun is declinable; plivati delfinom is also usual.