empty-headed vs lightheaded

empty-headed and lightheaded both are adjectives.

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

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

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

empty-headed (adjective)	lightheaded (adjective)
lacking seriousness; given to frivolity	lacking seriousness; given to frivolity
	weak and likely to lose consciousness