| Idiom | Meaning | Example |
| on time |
not late, at the scheduled time
|
Mary is always on time. She is very punctual.
|
| on top of |
informed, prepared, up on
|
Addie stays on top of math by doing problems every day.
|
| on track |
in the right direction, on the rails
|
After a few problems, our project is back on track.
|
| on trial |
in court as a defendant, defending your actions
|
The man charged with the assault is on trial now. He's in court.
|
| on vacation |
having a holiday from work or school
|
I don't feel like getting up early when I'm on vacation.
|
| on your ass [B] |
wrong, misinformed, all wet
|
He doesn't know how to manage a business. He's on his ass!
|
| on your deathbed |
very ill, nearly dead
|
When I get a cold, you think I'm on my deathbed. Relax.
|
| on your guard |
careful, cautious
|
Be on your guard when you buy a used car - don't buy a lemon .
|
| on your own |
independent, supporting yourself
|
When you're on your own, you can stay out all night if you wish.
|
| on your side |
supporting you and your efforts
|
"I'm on your side," Kelly said. "I want you to pass this course."
|