If you tell someone to watch a particular person or thing, you are warning them to be careful that the person or thing does not get out of control or do something unpleasant. You really ought to watch these quiet types If you're watching the calories, don't have mayonnaise
If you are on the watch for something, you are expecting it to happen and you therefore pay attention to events so that you will notice it when it does happen. Environmentalists will be on the watch for damage to wildlife. = on the lookout
If you watch someone or something, you look at them, usually for a period of time, and pay attention to what is happening. The man was standing in his doorway watching him He watched the barman prepare the beer he had ordered Chris watched him sipping his brandy I watched as Amy ate a few nuts
If you watch people, especially children or animals, you are responsible for them, and make sure that they are not in danger. Parents can't be expected to watch their children 24 hours a day
You say `watch it' in order to warn someone to be careful, especially when you want to threaten them about what will happen if they are not careful. `Now watch it, Patsy,' the Sergeant told her
If you watch someone, you follow them secretly or spy on them. Ella was scared that someone was watching her
If someone keeps watch, they look and listen all the time, while other people are asleep or doing something else, so that they can warn them of danger or an attack. Jose, as usual, had climbed a tree to keep watch
You say to someone `you watch' or `just watch' when you are predicting that something will happen, and you are very confident that it will happen as you say. You watch. Things will get worse before they get better
A watch is a period of carefully looking and listening, often while other people are asleep and often as a military duty, so that you can warn them of danger or an attack. I had the first watch that May evening
If you watch a situation or event, you pay attention to it or you are aware of it, but you do not influence it. Human rights groups have been closely watching the case Annoyed commuters could only watch as the departure time ticked by
If you watch something on television or an event such as a sports match, you spend time looking at it, especially when you see it from the beginning to the end. I'd stayed up late to watch the film They spent a great deal of time watching television
If someone is being kept under watch, they are being guarded or observed all the time
If someone is on watch, they have the job of carefully looking and listening, often while other people are asleep and often as a military duty, so that they can warn them of danger or an attack. Apart from two men on watch in the engine-room, everyone was asleep
If you keep watch on events or a situation, you pay attention to what is happening, so that you can take action at the right moment. US officials have been keeping close watch on the situation