breather vs breathing spell

breather and breathing spell both are nouns.

Word	Noun	Adjective	Verb	Adverb
breather	Yes	No	No	No
breathing spell	Yes	No	No	No

As nouns, breather and breathing spell are synonyms defined as:

Other synonyms of breather include breath, breathing place, breathing space, breathing time.

breather (noun)	breathing spell (noun)
air passage provided by a retractable device containing intake and exhaust pipes; permits a submarine to stay submerged for extended periods of time	a short respite
a short respite