cloud nine vs blissfulness

cloud nine and blissfulness both are nouns.

Word	Noun	Adjective	Verb	Adverb
cloud nine	Yes	No	No	No
blissfulness	Yes	No	No	No

As nouns, cloud nine and blissfulness are synonyms defined as:

Other synonyms of cloud nine include bliss, seventh heaven, walking on air.

cloud nine (noun)	blissfulness (noun)
a state of extreme happiness	a state of extreme happiness