empty-headed vs featherbrained

empty-headed and featherbrained both are adjectives.

Word	Noun	Adjective	Verb	Adverb
empty-headed	No	Yes	No	No
featherbrained	No	Yes	No	No

As adjectives, empty-headed and featherbrained are synonyms defined as:

empty-headed and featherbrained: lacking seriousness; given to frivolity

Other synonyms of empty-headed include airheaded, dizzy, giddy, light-headed, lightheaded, silly.

empty-headed (adjective)	featherbrained (adjective)
lacking seriousness; given to frivolity	lacking seriousness; given to frivolity