under lock and key: secure; safely protected.

She keeps her most important possessions under lock and key.

girl holding a key

under one’s belt: resources and experience.

He has many years of experience working as an architect under his belt.

architect

under one’s nose: something unnoticed in front of a person.

Heidi was looking around for her stuffed animal, and it was right under her nose.

girl opening gifts

under someone’s thumb: under another person’s control.

He’s got her under his thumb.

couple at theater

under the circumstances: during a time of distress; a time of difficulty.

We tried to talk to her about her deceased husband’s estate and will, but under the circumstances, it wasn’t a good time.

woman crying

under the influence: drunk or high

He was under the influence of a strong narcotic when the police found him lying in the street.

drunk

under the weather: a little sick

Hubert is feeling under the weather today, so he’s not going to go to work.

man sick in bed

up and about: able to walk and do things after a sickness.

He’s finally able to get up and about after his heart operation.

man gardening

up for grabs: something is available to the first person who takes it.

This last piece of pizza is up for grabs. Who wants it?

pizza

Hmmmm! Pizza.

up in the air: uncertain

A lot of things are up in the air right now for Mohammed and Fosiya. They’re still trying to decide whether or not to get married.

hot air balloon

up to something: involved in some mischief.

What’s he up to now?

boy with slingshot

up to one’s ears: to have too much of something.

We’re up to our ears in zucchini by the middle of summer.

zuchinni

use it or lose it: if you have something, you should use it or else it won’t be available in the future.

A: He has great skill as a baseball player. He should play professionally.

B: Yeah, use it or lose it.

batter

use one’s head: to think clearly; to make good decisions.

She wasn’t using her head when she got all those tattoos.

woman with tatoos

(a) vicious circle: something happens repeatedly.

She’s stuck in a vicious circle at work.

circle

vote with one’s feet: to go to a new place; to move.

When the economy turned sour in Nevada, Alison and Chris voted with their feet and moved to Minnesota.

people walking