Knock off and Mark down

Knock off verb - To bring (as an action or operation) to an immediate end.

Mark down and knock off are semantically related In some cases you can use "Mark down" instead a verb "Knock off".

Mark down verb - Reduce the price of.

Knock off and mark down are semantically related in lower topic. Sometimes you can use "Knock off" instead a verb "Mark down", if it concerns topics such as depreciate, peel.