Answer: batty

AnswerCrossword Clue
BATTYSilly: Slang.
battya West Indian slang word for (a person's) bottom
battycrazy or eccentric
BATTYOff one's trolley
BATTYNutty as a fruitcake
BATTYCrackers
BATTYChiropterous
BATTYQuite daft
BATTYPixilated
BATTYDaft
BATTYOff one's rocker
BATTYCuckoo
BATTYBalmy
BATTYSilly: Colloq.
BATTYTetched.
BATTYCrazy
BATTYFoolish: Slang.
BATTYInsane: slang.
BATTYSilly
BATTYEccentric
BATTYEccentric, slangily
BATTYNot all there
BATTYNutso
BATTYOff-the-wall
BATTYBananas
BATTYLoco
BATTYFruity
BATTYBonkers
BATTYNuts
BATTYAround the bend