The Collaborative International Dictionary of English v.0.48:
Stabber \Stab"ber\ (st[a^]b"b[~e]r), n. 1. One who, or that which, stabs; a privy murderer. [1913 Webster] 2. (Naut.) A small marline spike; a pricker. [1913 Webster]WordNet (r) 3.0 (2006):
stabber n 1: someone who stabs another person