adverb In a direction away from the speaker or other reference point.
He drove off in a cloud of smoke.
adverb Into a state of non-operation or non-existence.
Please switch off the light when you leave.
adverb So as to remove or separate, or be removed or separated.
He bit off the end of the carrot.
adverb Specifying the number of some item in bills, parts lists, etc.
3 off 20 amp fuses
adverb Offstage.
noises off
adverb Used in various other ways specific to individual idiomatic phrases, e.g. bring off, show off, put off, tell off, etc. See the entry for the individual phrase.