Recognition caution
deep-six something
Meaning
Get rid of something or reject a plan so it will not go forward.
Tone & use
Informal and forceful. “Set aside” or “reject” is clearer in professional situations; do not use it to imply secretly destroying evidence.
Example
“After checking the budget, the organizers deep-sixed the expensive stage idea and chose a smaller setup.”
Never use this phrase to suggest hiding or destroying records that should be preserved.