izazivač

1. (in sport, competition) challenger
   Izazivač je nokautirao šampiona u trećoj rundi. — The challenger knocked out the champion in the third round.
2. instigator; inciter
   Policija je uhapsila izazivače nereda posle utakmice. — The police arrested the instigators of the riot after the match.
3. (of a disease) causative agent; pathogen
   Lekari još traže izazivača ove infekcije. — Doctors are still looking for the cause of this infection.

Usually followed by the genitive: izazivač nereda, izazivač bolesti.