thresh vs thresher

thresh is not a noun while thresher is a noun.

Word	Noun	Adjective	Verb	Adverb
thresh	No	No	Yes	No
thresher	Yes	No	No	No

thresh (noun)	thresher (noun)
	large pelagic shark of warm seas with a whiplike tail used to round up small fish on which to feed
	a farm machine for separating seeds or grain from the husks and straw

thresh (verb)	thresher (verb)
give a thrashing to; beat hard
beat the seeds out of a grain
move or stir about violently
move like a flail; thresh about