Latin: From the beginning; from the first act A party is said to be a trespasser ab initio, an estate to be good ab initio, an agreement or deed to be void ab initio, a marriage to be unlawful ab initio, and the like. 2. When a man enters upon lands or into the house of another by authority of law, and afterwards abuses that authority, he becomes a trespasser ab initio. And if an officer neglect to remove goods attached within a reasonable time and continue in possession, his entry becomes a trespass ab initio. 3. But in case of an authority in fact, to enter, an abuse of such authority will not, in general, subject the party to an action of trespass.