source: [日常の長野原みおがパジャマ姿で転げまわるGIF画像｜無料GIF画像検索 GIFMAGAZINE 43125]

verb with object

beat (a person or animal) repeatedly and violently with a stick or whip:

(一般に)〈物･人〉を繰り返し打つ, 激しくたたく.

e.g. she thrashed him across the head and shoulders

e.g. (as noun thrashing) : what he needs is a good thrashing.

hit (something) hard and repeatedly:

(体罰として)〈人〉を激しく打つ, 打ちのめす

e.g. the wind screeched and the mast thrashed the deck.

no object move in a violent and convulsive way:

〖～＋副詞〗 〈人が〉もがく, のたうち回る, 激しく動く (!〖副詞〗はabout, aroundなど方向の表現) .

e.g. he lay on the ground thrashing around in pain

〈手足･体の一部〉をばたつかせる, 激しく動かす(about, around)

e.g. with object : she thrashed her arms, attempting to swim.

no object (thrash around) struggle in a wild or desperate way to do something:

e.g. two months of thrashing around on my own have produced nothing.

informal defeat (someone) heavily in a contest or match:

｟くだけて･主に英｠ 〈対戦相手など〉に大勝する, 打ち負かす

e.g. I thrashed Pete at cards

e.g. with object and complement : the Braves were thrashed 8–1 by the Mets.

no object move with brute determination or violent movements:

〈物が〉(水面などを)激しく打つ

e.g. I wrench the steering wheel back and thrash on up the hill.

rare term for thresh (sense 1) .

1. usually in singular a violent or noisy movement, typically involving hitting something repeatedly:

〖単数形で〗激しく動く［打つ, たたく］こと

e.g. the thrash of the waves.

2. a short, fast, loud piece or passage of rock music.

(also thrash metal) a style of fast, loud, harsh-sounding rock music, combining elements of punk and heavy metal.

｟くだけて｠ 〘楽〙 スラッシュ(メタル)(thrash metal)〘過激で疾走感のあるヘビーメタル〙

discuss something thoroughly and honestly.

Old English, variant of thresh (an early sense). Current senses of the noun date from the mid 19th century.