Something that deters: a deterrent to theft. (noun)
A retaliatory means of discouraging enemy attack: a nuclear deterrent. (noun)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "deterrent" in a sentence
"It would seem that shutting off cell phone service in subway tunnels as a deterrent is a waste of time."
"And I think sometimes they will do it for, you know, what they call deterrent value, to let the other 2,000 people out there in their situation know that you better not cross the line or this is what's going to happen to you."
"In the matter of defence, we should not overlook the fact that one of the key elements in any adversary's assessment of the effectivenes of our deterrent is the state of the resolution and will of the North Atlantic Alliance."