blef

1. bluff
   Nije imao ništa u ruci, to je bio čist blef. — He had nothing in his hand, it was a pure bluff.
   Njihove pretnje su samo blef. — Their threats are just a bluff.
2. colloq. a sham; a con
   Taj kurs je totalni blef, ništa nisam naučio. — That course is a total con, I didn't learn anything.

The verb is blefirati "to bluff".