The Collaborative International Dictionary of English v.0.48:

Determent \De*ter"ment\, n. [From Deter.]
   The act of deterring; also, that which deters. --Boyle.
   [1913 Webster]

WordNet (r) 3.0 (2006):

determent
    n 1: a communication that makes you afraid to try something
         [syn: determent, deterrence, intimidation]