breathing out vs exhalation

breathing out and exhalation both are nouns.

Word	Noun	Adjective	Verb	Adverb
breathing out	Yes	No	No	No
exhalation	Yes	No	No	No

As nouns, breathing out and exhalation are synonyms defined as:

Other synonyms of breathing out include expiration.

breathing out (noun)	exhalation (noun)
the act of expelling air from the lungs	the act of expelling air from the lungs
	exhaled breath