slice something ↔ off phrasal verb ( see also ↑ slice )
1 . to remove part of something by cutting it with one movement of a sharp knife or edge SYN cut off :
His knife had slipped and sliced off the top of his finger.
2 . to reduce a cost or total by a particular amount quickly and easily
slice something off something
By using volunteers, we were able to slice £10,000 off the cost of the project.