More silly, eccentric, or giddy than something else; comparative form of daffy.
From 'daffy' (silly, scatterbrained) + comparative suffix '-er'. Daffy likely derives from Old English dæf (meek, silly) or is connected to daft, both describing foolishness or lightheartedness.
The word 'daffy' became wildly popular in early 20th-century American slang, especially through Looney Tunes' Daffy Duck (named 1937), making it one of the few cartoon characters whose names became common English adjectives describing real people's behavior.
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