Any of several New World passerine songbirds, of the genera Toxostoma, Allenia, Margarops, Oreoscoptes and Ramphocinclus in the family Mimidae, that have a long, downward-curved beak.
A thresher shark.
(informal) A fan of thrash metal music.
Etymology
Originally a variant of thresher; equivalent to thrash + -er.