bezbrojan

1. countless; innumerable
   Na nebu su sijale bezbrojne zvezde. — Countless stars were shining in the sky.
   Posle bezbrojnih pokušaja, konačno je položio vozački. — After countless attempts, he finally passed his driving test.

Mostly used in the plural; for "countless times" the indeclinable bezbroj is common: bezbroj puta.