Ab Initio Legal Meaning and Definition

Here is a simplified definition of the legal term Ab Initio.

Ab Initio (Latin, adverb & adjective)

  1. Meaning "from the beginning" or "from the inception," typically describes something that applies retroactively, right from the start. Example: An illegal contract, identified as 'void ab initio,' is null and void from the point of its creation, not just from the moment it is declared invalid.

  2. In property law, a person deemed a 'trespasser ab initio' violates legal entry authority onto a private property, and is therefore considered a trespasser from the initial entry moment. Example: A repairman, invited into a home, who subsequently steals from the homeowner, may be declared a 'trespasser ab initio.'