WordWeb Online

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

Derived forms: battier, battiest

See also: insane

Encyclopedia: Batty