A more thorough explanation:

A blank check is a type of check that is signed by the drawer but left blank as to the payee or the amount, or both. This means that the person who receives the check can fill in the amount and the name of the payee.

For example, if a person gives a blank check to their contractor to pay for home renovations, the contractor can fill in the amount they want to be paid and their own name as the payee. This can be risky because the contractor could potentially fill in a larger amount than what was agreed upon or even write the check to themselves.

It is important to be cautious when giving out blank checks and to only do so with people you trust.