adjective
Given to lighthearted silliness
Synonyms: empty-headed, featherbrained, flighty, frivolous, frothy, giddy, harebrained, lighthearted, scatterbrained, silly, birdbrained, dizzy
adjective
Afflicted with or exhibiting irrationality and mental unsoundness
Synonyms: crazy, dotty, brainsick, daft, demented, disordered, distraught, insane, lunatic, mad, maniac, maniacal, mentally ill, moonstruck, off, touched, unbalanced, unsound, wrong, doddering, bonkers, cracked, daffy, loony, bananas, batty, buggy, cuckoo, fruity, loco, nuts, nutty, screwy, wacky, crackers, non compos mentis, wild, doddery, senile