Source : Webster's Revised Unabridged Dictionary (1913)

Deterrent \De*ter"rent\, a. [L. deterrens, p. pr. of deterrere.
   See {Deter}.]
   Serving to deter. ``The deterrent principle.'' --E. Davis.

Deterrent \De*ter"rent\, n.
   That which deters or prevents.

Source : WordNet®

deterrent
     adj : tending to deter; "the deterrent effects of high prices"

deterrent
     n : something immaterial that interferes with or delays action
         or progress [syn: {hindrance}, {impediment}, {balk}, {baulk},
          {check}, {handicap}]