dot·ty 
(dŏtē)
(dŏtē)adj. dot·ti·er, dot·ti·est
1.
a. Mentally unbalanced; crazy.
b. Amusingly eccentric or unconventional.
c. Ridiculous or absurd: a dotty scheme.
2. Having a feeble or unsteady gait; shaky.
3. Obsessively infatuated or enamored.
[Probably alteration of Scots dottle, silly, from Middle English doten, to dote.]
dotti·ly adv.
dotti·ness n.