Synonyms for Thresher (same or very similar meaning)
WordNet sense 1 (a farm machine for separating seeds or grain from the husks and straw):
thrasher, threshing machineWordNet sense 2 (large pelagic shark of warm seas with a whiplike tail used to round up small fish on which to feed):
Alopius vulpinus, fox shark, thresher sharkFrom the ODE community, based on WordNetadd/edit