A more thorough explanation:

Definition: Having no legal effect; without binding force; VOID. The phrase null and void is a common redundancy.

Examples:

• The contract was declared null and void.
• The judge ruled that the evidence was null and could not be used in court.
• The defendant's plea was nullified when it was discovered that he had lied under oath.

These examples illustrate that when something is null, it is considered to have no legal value or effect. In the case of a contract being declared null and void, it means that the contract is no longer valid and cannot be enforced. Similarly, when evidence is deemed null, it cannot be used in court to support a case. And when a plea is nullified, it means that it is no longer valid and cannot be considered by the court.