A more thorough explanation:

Definition: A pusher is someone who sells illegal drugs.

Example: The police arrested a pusher who was selling cocaine on the street corner.

Explanation: The example shows how a pusher is someone who sells drugs that are not legal. This person is breaking the law and can be arrested by the police.

Additional Example: The pusher offered to sell me some marijuana, but I declined because I didn't want to get in trouble with the law.

Explanation: This example also shows how a pusher is someone who sells illegal drugs. The person in this example was offered drugs, but they made the right decision by refusing to buy them.