be off
phr. v.. B1 Intermediate Oxford
phr. v.. to leave a place or start a journey. You use this when you are ready to go right now.
phr. v.. to depart or leave a location; often used in the present tense to signal immediate departure or as an imperative.
I'm off to the shops now.
It is getting late, so I think I'll be off before the traffic gets too bad.
The explorers were off at dawn, hoping to reach the summit before the weather turned against them.
Usage
usually used in the present tense with 'be' or as a future intention.
Teaching tip
this is a very common spoken alternative to 'leave' or 'go'; it can also mean food has gone bad, but the departure sense is more frequent for learners.
Pitfall
I will off now.I'm off now.the phrase requires the verb 'be' to function correctly as a predicate.