off

In a direction away from the speaker or other reference point.

“He drove off in a cloud of smoke.”

Into a state of non-operation or non-existence.

“Please switch off the light when you leave.”

So as to remove or separate, or be removed or separated.

“He bit off the end of the carrot.”

“Some branches were sawn off.”

theatreOffstage.

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.

From a particular thing or place or position (‘forth’ is obsolete)

“ran away from the lion”

“wanted to get away from there”

“sent the children away to boarding school”

At a distance in space or time

“the boat was 5 miles off (or away)”

“the party is still 2 weeks off (or away)”

“away back in the 18th century”

No longer on or in contact or attached

“clean off the dirt”

“he shaved off his mustache”

Inoperative, disabled.

“All the lights are off.”

Cancelled; not happening.

“The party's off because the hostess is sick.”

Not fitted; not being worn.

“Your feet will feel better once those tight boots are off.”

“The drink spilled out of the bottle because the top was off.”

Rancid, rotten, gone bad.

“This milk is off!”

auslangDisgusting, repulsive, abhorrent.

Less than normal, in temperament or in result.

“sales are off this quarter”

Inappropriate; untoward.

“I felt that his comments were a bit off.”

'poorly off'etc.in 'how?' questionsCircumstanced.

“Our family used to be well off; now we're very badly off.”

“How are you off for milk? Shall I get you some more from the shop?”

Started on the way.

“off to see the wizard”

“And they're off! Whatsmyname takes an early lead, with Remember The Mane behind by a nose.”

Far; off to the side.

“He took me down the corridor and into an off room.”

“the off horse or ox in a team, in distinction from the nigh or near horse”

Designating a time when one is not strictly attentive to business or affairs, or is absent from a post, and, hence, a time when affairs are not urgent.

“He took an off day for fishing.  an off year in politics; the off season”

Designating a time when one is not performing to the best of one's abilities.

of a dish on a menuPresently unavailable.

“— I'll have the chicken please.”

“— Sorry, chicken's off today.”

UKin relation to a vehicleOn the side furthest from the kerb (the right-hand side if one drives on the left).

“The off front wheel came loose.”

Not positioned upon, or away from a position upon.

“He's off the roof now.”

“I took it off the table.”

Detached, separated, excluded or disconnected from; away from a position of attachment or connection to.

“The phone is off the hook”

“The coat fell off the peg.”

Used to indicate the location or direction of one thing relative to another, implying adjacency or accessibility via.

“His office is off this corridor on the right.”

“We're just off the main road.”

Used to express location at sea relative to land or mainland.

“The island is 23 miles off the cape.”

Removed or subtracted from.

“There's 20% off the list price.”

No longer wanting or taking.

“He's been off his feed since Tuesday.”

“He's off his meds again.”

colloquialmore properly 'from'Out of the possession of.

“He didn't buy it off him. He stole it off him.”

Placed after a number (of products or parts, as if a unit), in commerce or engineering.

“Tantalum bar 6 off 3/8" Dia × 12" — Atom, Great Britain Atomic Energy Authority, 1972”

“samples submitted … 12 off Thermistors type 1K3A531 … — BSI test report for shock and vibration testing, 2000”

slangTo kill.

SingaporePhilippinesTo switch off.

“Can you off the light?”

Kill intentionally and with premeditation

“The mafia boss ordered his enemies murdered”

'at the off'etc.Beginning; starting point.

“He has been very obviously an untrustworthy narrator right from the off.”