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1. Informal or slang term for mentally irregular
   - balmy [archaic], barmy, bats, batty, bonkers, buggy [N. Amer], cracked, crackers, daft, fruity, haywire, kooky, kookie, loco, loony, loopy, nuts, nutty, round the bend, around the bend, wacky, whacky, daft as a brush [Brit], wacko, round the twist [Brit]
    
2. Intensely enthusiastic about or preoccupied with
   "dotty about cars and racing"
   - crazy, wild, gaga

Derived forms: dottiest, dottier

See also: enthusiastic, insane, keen

Encyclopedia: Dotty