What it means
A void contract has no legal effect from the outset — it is as if it never existed. A contract may be void because it is missing an essential element (such as consideration), is for an illegal purpose, or is impossible to perform. This differs from a voidable contract, which is valid until one party chooses to cancel it. Because a void contract was never binding, neither party can sue on it, though a party may sometimes recover money or property already transferred.
How it's used
Because the agreement required one party to do something illegal, the court held it was a void contract and refused to enforce it.