Meaning of “off” - Learner’s Dictionary

off

adjective [ never before noun ] uk us /ɒf/
NOT CORRECT

not correct:

Our sales figures were off by ten percent.
FOOD

B2 If food or drink is off, it is not now fresh and good to eat or drink:

This milk smells off.
NOT AT WORK

A2 not at work:

He's off today - I think he's ill.
→ See also off-chance

(Definition of “off adjective” from the Cambridge Learner’s Dictionary © Cambridge University Press)