stay up

verb

I usually stay up late to finish my work.

意味（1）

(literally) To remain in a raised or upright position.

These trousers are too big around the waist. They won't stay up.

意味（2）

To remain awake, to not go to bed.

My plane leaves at 6:00 in the morning, so I plan to stay up until then and sleep on the plane.

意味（3）

(euphemistic) To maintain an erection.

He told his lover he has a problem staying up.