Literally, Spanish for 'male'. In English, used of a man to describe stereotypically male characteristics such as virility, strength and toughness, particularly with regard to sexual attractiveness.
Russell Crowe is kind of irritating but he is really macho, so women like him.
Harmlessly clueless; having (or requiring) little in the way of mental ability.
Her boyfriend is nice, but he's just such a beer-drinking, football-watching dumbshit.
I love those totally dumbshit Will Ferrell comedies, like 'Anchorman.'