breaststroke vs breaststroker

breaststroke and breaststroker both are nouns.

Word	Noun	Adjective	Verb	Adverb
breaststroke	Yes	No	Yes	No
breaststroker	Yes	No	No	No

breaststroke (noun)	breaststroker (noun)
a swimming stroke; the arms are extended together in front of the head and swept back on either side accompanied by a frog kick	someone who swims the breaststroke

breaststroke (verb)	breaststroker (verb)
swim with the face down and extend the arms forward and outward while kicking with the leg