bats

from WordNet (r) 3.0 (2006)

bats
    adj 1: informal or slang terms for mentally irregular; "it used
           to drive my husband balmy" [syn: {balmy}, {barmy},
           {bats}, {batty}, {bonkers}, {buggy}, {cracked},
           {crackers}, {daft}, {dotty}, {fruity}, {haywire},
           {kooky}, {kookie}, {loco}, {loony}, {loopy}, {nuts},
           {nutty}, {round the bend}, {around the bend}, {wacky},
           {whacky}]

from The Collaborative International Dictionary of English v.0.48

bats \bats\ (b[a^]ts), a.
   Crazy; insane; loony; demented; batty.
   [PJC]

from Moby Thesaurus II by Grady Ward, 1.0

38 Moby Thesaurus words for "bats":
      balmy, bananas, barmy, batty, beany, bonkers, buggy, bughouse,
      bugs, crackers, cuckoo, daffy, dippy, dotty, flaky, flipped,
      freaked-out, fruitcakey, fruity, gaga, goofy, haywire,
      just plain nuts, kooky, loony, loopy, nuts, nutty, off the hinges,
      off the track, off the wall, potty, round the bend, screwball,
      screwballs, screwy, slaphappy, wacky

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