On occasion
Occasionally.We go to my favorite restaurant on occasion.
On no account
For no reason, absolutely not.On no account will I let my friend borrow my laptop computer.
On medication
Taking medicine for a current medical problem.The woman has been on medication for many years.
On lunch
To be on a lunch break.I was on lunch when my friend phoned.
On again, off again
To be unsettled or changeable or uncertain.The plans for the fireworks display were on again, off again because of the windy weather.
Off one`s chest
Not bothering you anymore (usually used for a problem).I talked to my friend and I was able to get my problem off my chest.
Off one`s back
Not bothering someone .I wish that my father would get off my back and stop asking me when I am going to look for a job.
Off on the wrong foot
To start something under bad circumstances.I tried to talk to my new neighbor but it seems that we are off on the wrong foot already.
Off limits
Forbidden.The factory was off limits to everybody except the workers who worked there.
Off like a shot
To go away quickly.The children were off like a shot when the school bell rang.