[1] : WordNet (r) 2.0

fail-safe
     adj 1: guaranteed not to fail; "a fail-safe recipe for cheese
            souffle"
     2: eliminating danger by compensating automatically for a
        failure or malfunction; "a fail-safe device in a nuclear
        weapon to deactivate it automatically in the event of
        accident"

Failsafe >> F Words
Failsafe, definition of term: Failsafe
failsafe_pag1.html