1928 (n.) "tough guy," from Spanish macho "male animal," noun use of adjective meaning "masculine, virile," from Latin masculus (see masculine). As an adjective, first attested in English 1959.
The often exaggerated, aggressive virility of a male: “Jim likes to wear a torn T-shirt and a black leather jacket when he rides his motorcycle. I guess he thinks it makes him look macho.” The original Spanish word means “male.”