breathing in vs breath

breathing in and breath both are nouns.

Word	Noun	Adjective	Verb	Adverb
breathing in	Yes	No	No	No
breath	Yes	No	No	No

As nouns, breath is a hypernym of breathing in; that is, breath is a word with a broader meaning than breathing in:

breathing in: the act of inhaling; the drawing in of air (or other gases) as in breathing
breath: the process of taking in and expelling air during breathing

breathing in (noun)	breath (noun)
the act of inhaling; the drawing in of air (or other gases) as in breathing	the process of taking in and expelling air during breathing
	an indirect suggestion
	a slight movement of the air
	the air that is inhaled and exhaled in respiration
	a short respite