1.
If something comes off , it is successful or effective.
It was a good try but it didn’t quite come off...
PHRASAL VERB : V P
2.
If someone comes off worst in a contest or conflict, they are in the worst position after it. If they come off best, they are in the best position.
Some Democrats still have bitter memories of how, against all odds, they came off worst during the inquiry...
PHRASAL VERB : V P adv
3.
If you come off a drug or medicine, you stop taking it.
...people trying to come off tranquillizers.
PHRASAL VERB : no passive , V P n
4.
You say ‘come off it’ to someone to show them that you think what they are saying is untrue or wrong. ( INFORMAL, SPOKEN )
CONVENTION