breather vs sub

breather and sub both are nouns.

Word	Noun	Adjective	Verb	Adverb
breather	Yes	No	No	No
sub	Yes	No	Yes	No

breather (noun)	sub (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 submersible warship usually armed with torpedoes
a short respite	a large sandwich made of a long crusty roll split lengthwise and filled with meats and cheese (and tomato and onion and lettuce and condiments); different names are used in different sections of the United States

breather (verb)	sub (verb)
	be a substitute