Deep-six

Origin

From deep + six.

Maybe: depth of a grave (six feet).

Full definition of deep-six

Verb

1. (US, idiomatic) to throw something overboard from a ship
2. (US, idiomatic) to get rid of something unwantedFirst, the stark message to “eat less” of a particular food has been deep-sixed. - 28/01/2007, New York Times http://www.nytimes.com/2007/01/28/magazine/28nutritionism.t.html?pagewanted=2&ei=5087%0A&em&en=ce28063f61d4a925&ex=1170219600