Definition of "Thrash" :
noun: a swimming kick used while treading water
verb: beat thoroughly and conclusively in a competition or fight
verb: give a thrashing to; beat hard
verb: beat the seeds out of a grain
verb: move data into and out of core rather than performing useful computation
"The system is thrashing again!."
verb: beat so fast that (the heart's) output starts dropping until (it) does not manage to pump out blood at all
verb: move or stir about violently
"The feverish patient thrashed around in his bed."
verb: dance the slam dance