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1. Ludicrous, foolish
   "gave me a whacky reason for not going";
   - cockamamie [N. Amer], cockamamy [N. Amer], goofy, sappy, silly, wacky, zany
    
2. Informal or slang term meaning insane, strange, eccentric or stupid
   "it used to drive my husband whacky";
   - balmy [archaic], barmy, bats, batty, bonkers, buggy [N. Amer], cracked, crackers, daft, dotty, fruity, haywire, kooky, kookie, loco, loony, loopy, nuts, nutty, round the bend, around the bend, wacky, dippy, daffy, wacko, daft as a brush [Brit], potty [Brit], nutsy [N. Amer], round the twist [Brit], cuckoo

Derived forms: whackiest, whackier

See also: daft, dumb, foolish, insane, stupid

Encyclopedia: Whacky