macho; hypermasculine
Describes a person, attitude, or behavior that is aggressively masculine or macho. Often used critically or humorously.
He has a macho way of thinking.
muscular man; muscle-bound guy
Refers specifically to a man with a heavily muscled physique, often in a bodybuilding or fitness context. Can be used admiringly or jokingly.
There are a lot of muscular guys at the gym.
He worked out every day and became muscular.
She seems to like muscular guys.
He always talks in a macho, tough-guy way.
ガリガリ describes a thin, skinny build, the opposite physical type from a muscular マッチョ.
貧弱 describes a weak, frail body or build, contrasting with the strong, muscular image of マッチョ.
マッチ means a match (for lighting fire) or a sports match, while マッチョ describes a muscular or macho person; only the first syllables sound alike.
Borrowed from Spanish 'macho' via English 'macho'. The Japanese form マッチョ reflects the English pronunciation with a geminated consonant.