“Be off”: phrasal verb meaning.

be off
To go out, leave a place in order to go to another place.

Other examples of “be off” phrasal verb in a sentence

  • I’ve finished work for today. I’m off! Bye!
  • I think I’ll be off. See you tomorrow!
  • I’m off to the bar. I’ll be back in 1 hour.

“Be off”: use in context explanation

Dick’s been having a toothache for some time now (for a long period of time). He hasn’t been to the dentist’s yet because he is very scared of it. He always waits until the last moment before he goes to the dentist. The toothache has become very strong though, so Dick has no other choice at this point. He has to be off and fix his tooth. He’s finally found the courage to go. He takes his teddy bear with him to help him in this difficult moment and leaves the house.