Kenneth G. Wilson (1923–). The Columbia Guide to Standard American English. 1993.
guy (n., v.)
The noun is Casual as a term of direct address to a man or boy or sometimes as a plural for mixed groups (although some women don’t like it) or groups of males or females: Have you guys seen my briefcase? The referent is also male or female in uses such as We need to be able to tell the good guys from the bad guys and Are you a good guy or a bad guy? wherein good guys and bad guys are specialized terms for heroes and villains, respectively; these uses are Conversational and Informal. The verb guy is somewhat literary or old-fashioned in the sense “to tease or make fun of,” as in My friends guyed me unmercifully over my blunder.
