učinak

1. effect; result
   Lek nije imao nikakav učinak. — The medicine had no effect.
   Nove mere su dale dobar učinak. — The new measures produced a good result.
2. (of a worker, player) performance; output
   Plata zavisi od radnog učinka. — The pay depends on work performance.
   Njegov učinak na utakmici bio je 25 poena. — He scored 25 points in the game.

In the sense of "effect", everyday speech often prefers efekat.