from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Mentally unbalanced; crazy.
- adj. Amusingly eccentric or unconventional.
- adj. Ridiculous or absurd: a dotty scheme.
- adj. Having a feeble or unsteady gait; shaky.
- adj. Obsessively infatuated or enamored.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. Having many dots.
- adj. Mildly insane or excessively preoccupied; often, senile.
from the GNU version of the Collaborative International Dictionary of English
- adj. Composed of, or characterized by, dots.
- adj. Unsteady in gait; hence, feeble; half-witted.
from The Century Dictionary and Cyclopedia
- Having dots; covered or characterized by dots: as, a low, dotty underwood.
- Of unsteady gait; feeble and tottering, as from stiffness or lameness: as, to be a little dotty on one's feet.
- Feeble-minded; silly.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- adj. informal or slang terms for mentally irregular
- adj. intensely enthusiastic about or preoccupied with
Probably alteration of Scots dottle, silly, from Middle English doten, to dote.(American Heritage® Dictionary of the English Language, Fourth Edition)
dot + -y (Wiktionary)