The compound "wise-guy" is a modern American English formation from the early 20th century. It combines the adjective "wise," with its Old English roots in the Proto-Germanic wīsaz (meaning "knowledgeable"), and the informal noun "guy," which evolved from the personal name Guy, famously associated with Guy Fawkes. The term's logic is ironically sarcastic; it literally describes a "wise man," but its usage implies a person who is falsely or pretentiously wise, using cleverness in an annoying or insolent way. This evolution from a literal descriptor to a term of mild contempt reflects a common linguistic pattern where compounds acquire idiomatic, often pejorative, meanings distinct from their constituent parts.

Structure: wise (adjective) + guy (noun) wise: From Old English wīs, meaning "wise, learned, prudent." It functions as an adjective modifying the noun. guy: From the name Guy, originally a French name, but in this compound, it functions as a colloquial noun meaning "man, fellow."