mužjak

1. (of animals) male
   Mužjak pauna ima šareno perje. — The male peacock has colourful feathers.
   Da li je vaša mačka mužjak ili ženka? — Is your cat a male or a female?
2. colloq. ironic derog. (of a man) he-man; macho; alpha male
   Glumi pravog mužjaka pred devojkama. — He puts on a macho act in front of the girls.

Applied to a man, the word usually sounds ironic, crude or derogatory; the exact tone depends on context.