Synonyms of featherbrained

2 Syllables
scatty, silly, sillier, dingdong, ditzy, simple, foolish, swimmy, flighty, giddy, flightier, flightiest, brainless, silliest
3 Syllables
frivolous, light-minded, nonserious, birdbrained, lightheaded
4 Syllables
muddleheaded, empty-headed, addleheaded, rattlebrained, harebrained, addlepated, addlebrained, scatterbrained