What Is the Meaning of “Ab Initio” in law

Ab Initio is a Latin legal maxim that means “from the beginning.”

When something is said to be void ab initio, it means it was invalid from the very start, as if it never legally existed.

It treats an act, contract, or order as having no legal effect from the moment it was created, not just from the time it was declared invalid.

For example:

• If a contract is signed under fraud, the court may declare the contract void ab initio, meaning the contract is considered never valid at all, not even for a moment.
• A marriage prohibited under law (for example, bigamy under the Hindu Marriage Act, 1955) is void ab initio, meaning it was never treated as legally valid.

In short, “Ab Initio” in the legal sense means “invalid from the very beginning.”