Other forms: machos
A man who's aggressively masculine can be described as macho. A boxer might try to intimidate his opponent by walking into the ring with a macho swagger.
To be macho is to display a tough, fierce, overly confident facade. A man who's macho would never cry or sip a cup of tea or pet a kitten, because none of these things would be seen as "manly" enough. In Spanish, macho means "male animal," from the Latin root masculus, also "male," but also "worthy of a man."