empty words vs hot air

empty words and hot air both are nouns.

Word	Noun	Adjective	Verb	Adverb
empty words	Yes	No	No	No
hot air	Yes	No	No	No

As nouns, empty words and hot air are synonyms defined as:

Other synonyms of empty words include empty talk, palaver, rhetoric.

empty words (noun)	hot air (noun)
loud and confused and empty talk	loud and confused and empty talk
	air that has been heated and tends to rise