| Idiom | Meaning | Example |
| on your toes |
ready, alert
|
I have to be on my toes in her class. I have to listen and think.
|
| on your way |
traveling, leaving, on the road home
|
You can be on your way as soon as the tire is repaired.
|
| once-over |
(See give it the once-over)
|
|
| once in a blue moon |
very seldom, rarely, in a long time
|
"Have you heard from Paul?" "Once in a blue moon he calls,
maybe once a year."
|
| once upon a time |
a long time ago, at one time
|
Once upon a time, there was a king named Arthur...
|
| one and the same |
the same as, not different, part and parcel
|
Some people believe abortion and murder are one and the same thing.
|
| one at a time |
one then another, one by one
|
Don't push, kids! It's one at a time.
|
| one born every minute |
many easy customers, lots of suckers
|
"There's lots of suckers," he said. "There's one born every minute!"
|
| one brick short of a full load |
mentally slow, not all there
|
I'm okay, but you may be one brick short of a full load. Ha ha.
|
| one by one |
one then another; one at a time, single file
|
One by one the children entered the shelter.
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