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1. Informal or slang term meaning insane, strange, eccentric or stupid
   "it used to drive my husband loony";
   - balmy [archaic, slang], barmy [slang], bats [slang], batty [slang], bonkers [slang], buggy [N. Amer, slang], cracked [slang], crackers [slang], daft [Brit, slang], dotty [slang], fruity [slang], haywire [slang], kooky [slang], kookie [slang], loco [slang], loopy [slang], nuts [slang], nutty [slang], round the bend [slang], around the bend [slang], wacky [slang], whacky [slang], doolally [Brit, slang], dippy [slang], daffy [slang], nutsy [N. Amer, slang], potty [Brit, slang], daft as a brush [Brit, slang], round the twist [Brit, slang], wacko [slang], dumbass [N. Amer, slang], bughouse [N. Amer, slang], cuckoo [slang], mental [slang], barking mad [Brit, slang], barking [Brit, slang]

1. An insane person
   - lunatic, madman, maniac, crazy [N. Amer, informal], looney [informal], nutcase [informal], headcase [informal]

Sounds like: lo

Derived forms: loonier, loonies, looniest

See also: basket case [informal], fruitcake [informal], insane, mentalist [Brit, informal], nutbar [N. Amer, informal], nutcake [US, informal], nutjob [informal], nutter [Brit, informal], wackadoodle [N. Amer, informal], wackjob [N. Amer, informal], wacko [informal], whackjob [N. Amer, informal], whacko [informal]

Type of: diseased person, sick person, sufferer

Encyclopedia: Loony