verb

• (software) To extensively test a software system, giving a program various inputs and observing the behavior and outputs that result.
• (computing) In computer architecture, to cause or undergo poor performance of a virtual memory (or paging) system.

noun

• (countable) A beat or blow; the sound of beating.
  "Even among friends at the dinner-table he talked as though he were denouncing them, or someone else, on a platform; he measured his phrases, built his sentences, cumulated his effects, and pounded his opponents, real or imagined. His humor was glow, like iron at dull heat; his blow was elementary, like the thrash of a whale."
• (music, uncountable) Ellipsis of thrash metal.