lightheaded vs light-headed

lightheaded and light-headed both are adjectives.

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

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

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

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

Other synonyms of lightheaded include faint, light, swooning.

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