I must be off

I must be off

I have to leave. A somewhat formal and dated expression. Adam's waiting for me, so I must be off. Ooh, the train comes in five minutes, so I must be off!
See also: must, off
Farlex Dictionary of Idioms.

I must be off.

an expression announcing the speaker's intention of leaving. Bill: It's late. I must be off. Bob: Me, too. I'm out of here. Sue: I must be off. John: The game's not over yet. Sue: I've seen enough.
See also: must, off
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.
See also:
  • (one) (had) better be off
  • (I've) got to take off
  • (Now) where was I?
  • be off with you
  • be off for (something)
  • be off for sth
  • be well off for (something)
  • be well off for something
  • break off
  • base off (of) (something else)