deep-six
/ˈdiːpsɪks/verb
with obj.
- N. Amer. informal destroy or dispose of (something) irretrievably〈北美, 非正式〉毁灭, 摒弃：
someone had deliberately deep-sixed evidence.
有人故意毁灭了证据。
词源
1920s （as the deep six 'the grave'）： perhaps from the custom of burial at sea at a depth of six fathoms.