Corrected entry: When Somerset and Mills are in Mills' apartment going over the crime scene photos of the greed victim, Somerset states that attrition is when you feel remorse for a sin but not because you love God. Attrition is the act of thinning out the numbers of a group in order to achieve victory over them. The word Somerset was looking for is "contrition" (or "imperfect contrition" if you want to get technical).
Phaneron
10th Mar 2016
Correction: Theologically, "contrition" refers to "sorrow for and detestation of sin with a true purpose of amendment", while "attrition", or "imperfect contrition" refers to "sorrow, but not contrition, for sin." In other words, theologically speaking, "attrition" is the act of feeling guilty for a sin, not out true remorse, but more because of fear.