breathless vs breathing

breathless is not a noun while breathing is a noun.

Word	Noun	Adjective	Verb	Adverb
breathless	No	Yes	No	No
breathing	Yes	Yes	No	No

breathless (noun)	breathing (noun)
	the bodily process of inhalation and exhalation; the process of taking in oxygen from inhaled air and releasing carbon dioxide by exhalation

breathless (adjective)	breathing (adjective)
not breathing or able to breathe except with difficulty	passing or able to pass air in and out of the lungs normally; sometimes used in combination
appearing dead; not breathing or having no perceptible pulse
tending to cause suspension of regular breathing