daffy

The word 'daffy' emerged in the late 19th century as British slang. It is most convincingly derived from 'daff,' an obsolete northern English dialect term for a simpleton or fool, which itself may have originated from 'dafte,' a Middle English variant of 'dafed' meaning 'stupid.' The '-y' suffix is a common English adjectival ending. The word's popularization was significantly boosted by the 1930s Warner Bros. cartoon character Daffy Duck, whose zany, eccentric personality perfectly embodied and cemented the modern meaning of being amusingly silly.

This word is a simplex. It is an English slang formation, likely from the given name "Daffy," a pet form of "Daffodil," or influenced by the older word "daff" meaning "a simpleton."