What is a common phrasal verb that means to "cancel"?

The phrase "call off" is indeed a common phrasal verb used to mean "cancel." When you call off an event, you are indicating that it will no longer take place. This phrase is frequently used in various contexts, such as calling off a meeting, a sports game, or any planned activity that will not go ahead as intended.

The structure of phrasal verbs often combines a verb with a preposition or adverb, and in this case, "call off" directly conveys the action of voiding or nullifying something that was scheduled. It is understood in casual conversation and formal settings alike, making it a versatile term.

In contrast, the other options convey different meanings and uses. "Put off" relates to delaying or postponing something rather than canceling it outright. "Carry on" means to continue with an action or task, which is the opposite of canceling. "Turn down" generally refers to rejecting or declining an offer or invitation, not necessarily related to cancellation. Thus, "call off" is the most appropriate choice for indicating the cancellation of an event or plan.