'featherbrained' definitions:

Definition of 'featherbrained'

(from WordNet)
adjective
Lacking seriousness; given to frivolity; "a dizzy blonde"; "light-headed teenagers"; "silly giggles" [syn: airheaded, dizzy, empty-headed, featherbrained, giddy, light-headed, lightheaded, silly]

Definition of 'featherbrained'

From: GCIDE
  • featherbrained \feath"er*brained\, feather-brained \feath"er-brained\, a. Giddy; frivolous; lacking seriousness; given to frivolity; feather-headed. [Colloq.]
  • Syn: airheaded, dizzy, empty-headed, giddy, lightheaded, light-headed, silly. [1913 Webster + WordNet 1.5]

Synonyms of 'featherbrained'

From: Moby Thesaurus