(a.) Wild; giddy; volatile; heedless.

absurd adventurous arbitrary audacious balmy bold brainless capricious cranky crazy crotchety daredevil daring death-defying dizzy empty-headed fanciful fantasied fantastic featherbrained featherheaded fire-eating flaky flighty fluttery foolhardy forward freakish frivolous gaga giddy giddy-brained giddy-headed giddy-pated giddy-witted harebrain humorsome insane kinky loony madbrain madbrained madcap maggoty moody motiveless notional petulant potty preposterous presumptuous quirky rattlebrained rattleheaded rattlepated scatterbrained scramblebrained shatterbrained silly skittish temperamental thoughtless unreasonable unrestrained vagarious vagrant wacky wanton wayward whimsical wild wild-ass witless