adj. legal Latin meaning "for the purposes of the legal action only." Most often the term applies to a parent who files a lawsuit for his or her minor child as "guardian at litem" (guardian just for the purposes of the lawsuit) or for a person who is incompetent. Either at the time the lawsuit is filed or shortly thereafter, the parent petitions the court to allow him/her to be guardian ad litem, which is brought ex parte (without a noticed hearing) and is almost always granted. A person acting ad litem has the responsibility to pursue the lawsuit and to account for the money recovered for damages. If a child in such a lawsuit reaches majority (18 in most states) while the suit is pending, the ad litem guardianship terminates and the "new" adult can run his/her own lawsuit. Some courts require an order terminating the guardianship ad litem upon proof of coming of age.