harebrained (adj.)
- absurd
- adventurous
- arbitrary
- audacious
- balmy
- bold
- brainless
- capricious
- cranky
- crazy
- crotchety
- daredevil
- daring
- dizzy
- empty-headed
- fanciful
- fantastic
- featherbrained
- flaky
- flighty
- foolhardy
- forward
- freakish
- frivolous
- gaga
- giddy
- insane
- kinky
- loony
- madcap
- maggoty
- moody
- motiveless
- notional
- petulant
- potty
- preposterous
- presumptuous
- quirky
- rattlebrained
- rattlepated
- scatterbrained
- silly
- skittish
- temperamental
- thoughtless
- unreasonable
- unrestrained
- vagrant
- wacky
- wanton
- wayward
- whimsical
- wild
- witless
