gain vs gainer

gain and gainer both are nouns.

Word	Noun	Adjective	Verb	Adverb
gain	Yes	No	Yes	No
gainer	Yes	No	No	No

gain (noun)	gainer (noun)
the amount of increase in signal power or voltage or current expressed as the ratio of output to input	a dive in which the diver throws the feet forward to complete a full backward somersault and enters the water feet first and facing away from the diving board
the advantageous quality of being beneficial	a person who gains (gains an advantage or gains profits)
the amount by which the revenue of a business exceeds its cost of operating	a person who gains weight
a quantity that is added

gain (verb)	gainer (verb)
increase (one's body weight)
rise in rate or price
increase or develop
obtain advantages, such as points, etc.
reach a destination, either real or abstract
earn on some commercial or business transaction; earn as salary or wages
win something through one's efforts
derive a benefit from
obtain