1 [with object] separate grain from (corn or other crops), typically with a flail or by the action of a revolving mechanism:machinery that can reap and thresh corn in the same process (as noun threshing)farm workers started the afternoon’s threshing
2 /θreʃ/ [no object] move violently; thrash:a creature threshing in a net [with object]:it threshes its wings frantically overhead