threshing machine vs thrasher

threshing machine and thrasher both are nouns.

Word	Noun	Adjective	Verb	Adverb
threshing machine	Yes	No	No	No
thrasher	Yes	No	No	No

As nouns, threshing machine and thrasher are synonyms defined as:

threshing machine and thrasher: a farm machine for separating seeds or grain from the husks and straw

Other synonyms of threshing machine include thresher.

threshing machine (noun)	thrasher (noun)
a farm machine for separating seeds or grain from the husks and straw	thrush-like American songbird able to mimic other birdsongs
	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