Keep an eye on someone - something

Keep an eye on someone/something

Meaning:

Watch someone/something carefully to make sure everything is all right

If you keep an eye on someone or something, you watch him/her/it carefully because you don't trust him/her or want to see what happens.


Example:

He can be very dangerous. Always keep an eye on him.

They have been keeping an eye on the volcano day and night for more than a year.