blissfulness vs walking on air

blissfulness and walking on air both are nouns.

Word	Noun	Adjective	Verb	Adverb
blissfulness	Yes	No	No	No
walking on air	Yes	No	No	No

As nouns, blissfulness and walking on air are synonyms defined as:

Other synonyms of blissfulness include bliss, cloud nine, seventh heaven.

blissfulness (noun)	walking on air (noun)
a state of extreme happiness	a state of extreme happiness