1 hit sb many times
ADV. soundly That boy deserves to be soundly thrashed!
PREP. with He thrashed the poor servant with his stick.
2 move your arms and legs in an uncontrolled way
ADV. helplessly, violently, wildly | about, around The cow fell on its side and thrashed about wildly.
3 defeat sb easily in a game
ADV. soundly The visiting side were soundly thrashed.