featherbrained vs lightheaded

featherbrained and lightheaded both are adjectives.

Word	Noun	Adjective	Verb	Adverb
featherbrained	No	Yes	No	No
lightheaded	No	Yes	No	No

As adjectives, featherbrained and lightheaded are synonyms defined as:

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

featherbrained (adjective)	lightheaded (adjective)
lacking seriousness; given to frivolity	lacking seriousness; given to frivolity
	weak and likely to lose consciousness