To crush something means to press it very hard so that its shape is destroyed or so that it breaks into pieces.

To crush a protest or movement, or a group of opponents, means to defeat it completely, usually by force.

If you are crushed by something, it upsets you a great deal.

If you are crushed against someone or something, you are pushed or pressed against them.

A crush is a crowd of people close together, in which it is difficult to move.

If you have a crush on someone, you are in love with them but do not have a relationship with them.