From The Collaborative International Dictionary of English v.0.48 [gcide]:
Deterrent \De*ter"rent\, a. [L. deterrens, p. pr. of deterrere.
See Deter.]
Serving to deter. "The deterrent principle." --E. Davis.
[1913 Webster]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Deterrent \De*ter"rent\, n.
That which deters or prevents.
[1913 Webster]
From WordNet (r) 3.0 (2006) [wn]:
deterrent
adj 1: tending to deter; "the deterrent effects of high prices"
n 1: something immaterial that interferes with or delays action
or progress [syn: hindrance, hinderance, deterrent,
impediment, balk, baulk, check, handicap]