A worm is a small animal with a long thin body, no bones and no legs.

If animals or people have worms, worms are living in their intestines.

If you worm an animal, you give it medicine in order to kill the worms that are living in its intestines.

If you worm your way somewhere, you move there with difficulty, twisting or bending your body or making it narrow.

If you say that someone is worming their way to success, or is worming their way into someone else's affection, you disapprove of the way that they are gradually making someone trust them or like them, often in order to deceive them or gain some advantage.

If you call a person a worm, you are insulting them by saying that they have a very weak or unpleasant character and you have no respect for them.

A worm is a computer program that contains a virus which duplicates itself many times in a network.

If you say that someone is opening a can of worms, you are warning them that they are planning to do or talk about something which is much more complicated, unpleasant, or difficult than they realize and which might be better left alone.

If you say that the worm turns, you mean that someone who usually obeys another person or accepts their bad behaviour unexpectedly starts resisting that person or expresses their anger.