Definition of "fail-safe" []

• Capable of compensating automatically and safely for a failure, as of a mechanism or power source. (adjective)
• Acting to discontinue a military attack on the occurrence of any of various predetermined conditions. (adjective)
• Guaranteed not to fail: "There is no fail-safe mechanism guaranteed either to contain or to restore presidential authority” ( Arthur M. Schlesinger, Jr.) (adjective)
• A fail-safe mechanism. (noun)
• To compensate automatically for failure. (verb-intransitive)

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.

• "But it is somewhat sobering to see all these so-called 'fail-safe' mechanisms failing.''"
• "Cameron was the maker of the blowout preventer, the so-called fail-safe device that neglected to automatically shut down the well."
• "Cameron made the blowout preventer for the well, a so-called fail-safe device that failed to automatically shut down the well."