I am under a lot of pressure
under one's breath
They are talking under their breath in the movie theater.
under a cloud
She has been under a cloud of depression since her dog died.
under the weather
I'm feeling a bit under the weather.
You're under arrest.
That man was under arrest for robbing a bank.
The police officer went under cover to look for the drug dealers.
under one's nose
He flirted with a girl under his wife's nose.