lightheadedness vs giddiness

lightheadedness and giddiness both are nouns.

Word	Noun	Adjective	Verb	Adverb
lightheadedness	Yes	No	No	No
giddiness	Yes	No	No	No

As nouns, lightheadedness and giddiness are synonyms defined as:

lightheadedness and giddiness: a reeling sensation; a feeling that you are about to fall

Other synonyms of lightheadedness include dizziness, vertigo.

lightheadedness (noun)	giddiness (noun)
a frivolous lack of prudence	an impulsive scatterbrained manner
a reeling sensation; a feeling that you are about to fall	a reeling sensation; a feeling that you are about to fall