empty talk vs meaninglessness

empty talk and meaninglessness both are nouns.

Word	Noun	Adjective	Verb	Adverb
empty talk	Yes	No	No	No
meaninglessness	Yes	No	No	No

As nouns, meaninglessness is a hypernym of empty talk; that is, meaninglessness is a word with a broader meaning than empty talk:

Other hypernyms of empty talk include bunk, hokum, nonsense, nonsensicality.

empty talk (noun)	meaninglessness (noun)
loud and confused and empty talk	the quality of having no value or significance
	a message that seems to convey no meaning