(~s)
1.
A ~ is a place from which you can see clearly in all directions.
Troops tried to set up a ~ post inside a refugee camp.
N-COUNT
2.
A ~ is someone who is watching for danger in order to warn other people about it.
N-COUNT
3.
If someone keeps a ~, especially on a boat, they look around all the time in order to make sure there is no danger.
He denied that he’d failed to keep a proper ~ that night.
PHRASE: V inflects