Without legal effect, legally null. If a contract is held to be ‘void’, it means that it does not exist in any legal sense. Contracts are often held to be ‘void ab initio’ (void from the outset) if one party was induced into the contract by duress.
No legal actions can arise from a void contract as it is not a contract, and therefore confers no rights or obligations. By the same token, a void contract need not be rescinded or otherwise reconciled.
Some legal instruments, judgments, or acts are automatically void by their nature, for example, a marriage where one spouse is already validly married (and their previous spouse is alive), a judgment from a Court which lacks jurisdiction, or a contract with a minor.