Definition of "deterrent"

deterrent

/dɪˈtɛɹənt/

adjective
comparative more deterrent, superlative most deterrent
1. Serving to deter, preventing something from happening.
noun
plural deterrents
1. Something that deters.
  Quotations
  The salarians believed the genophage would be used as a deterrent, a position the turians viewed as naive. Once the project was complete, the turians mass produced and deployed it. The krogan homeworld, their colonies, and all occupied worlds were infected.
  2008, BioWare, Mass Effect (Science Fiction), Redwood City: Electronic Arts, PC, scene: Krogan: Genophage Codex entry
  One argument made by proponents of the death penalty is that it is a strong deterrent to murder and other violent crimes, but evidence shows just the opposite. Whereas the last execution in Canada took place in 1962, in 2011 there were 598 murders in Canada and 14,610 in the United States.
  2014, Jimmy Carter, “Full Prisons and Legal Killing”, in A Call to Action: Women, Religion, Violence, and Power‎, Simon & Schuster, page 38