kooky(s = adj.all) around the bend, balmy, barmy, bats, batty, bonkers, buggy, cracked, crackers, daft, dotty, fruity, haywire, kookie, loco, loony, loopy, nuts, nutty, round the bend, wacky, whacky - informal or slang terms for mentally irregular; "it used to drive my husband balmy"
Derived form noun kook₁

kooky, adj. (kookier, kookiest) sl. crazy.

Derivative:
kookily adv. kookiness n.