under a cloud
Under suspicion; not trusted.
Joyce has been under a cloud since her roommate's bracelet disappeared.
The butcher is under a cloud because the inspectors found his scales were not honest.
Depressed, sad, discouraged.
Joe has been under a cloud since his dog died.
under age
Too young; not old enough; below legal age.
He could not enlist in the army because he was under age.
Rose was not allowed to enroll in the Life Saving Course because she was under age.
under arrest
Held by the police.
The man believed to have robbed the bank was placed under arrest.
The three boys were seen breaking into the school building and soon found themselves under arrest.
under construction
In the process of being built or repaired.
It is a good idea to take the train to work while the expressway is under construction.
under cover
Hidden; concealed.
The prisoners escaped under cover of darkness.
He kept his invention under cover until it was patented.
under fire
Being shot at or being attacked; hit by attacks or accusations; under attack.
The soldiers stood firm under fire of the enemy.
The principal was under fire for not sending the boys home who stole the car.
under lock and key
Secured; locked up; well protected.
Dad keeps all his valuables under lock and key.
under one's belt
In your stomach; eaten; or absorbed.
Once he had a good meal under his belt, the man loosened his tie and fell asleep.
Jones is talkative when he has a few drinks under his belt.
In your experience, memory or possession; learned or gotten successfully; gained by effort and skill.
Jim has to get a lot of algebra under his belt before the examination.
With three straight victories under their belts, the team went on to win the championship.