#1 thrash v. [thresh, lam, flail] give a thrashing to; beat hard. wn
#2 thrash v. [convulse, thresh, thresh about, thrash about, slash, toss, jactitate] move or stir about violently; "The feverish patient thrashed around in his bed". wn
#3 thrash n. a swimming kick used while treading water. wn
#4 thrash v. [slam dance, slam, mosh] dance the slam dance. wn
#5 thrash v. beat so fast that (the heart's) output starts dropping until (it) does not manage to pump out blood at all. wn
vizzz