Of a device: such that, if it fails, it does so in a way that will cause little or no harm to other devices and personnel.

(computing) To automatically switch processing from a failed component in a critical system to its live spare or backup component.

(military) In nuclear weapons strategy: encouraging deterrence by guaranteeing an immediate, automatic, and overwhelming response to an attack, even if the command-and-control infrastructure has been damaged by the enemy's first strike.

plural of fail dyke

(Scotland) A wall of turf.

to advance in one's career despite failures

Alternative form of feal and divot

(Internet slang) Bad.

(Internet slang) Utter, total failure, especially where success should have been reasonably expected.

Third-person singular simple present indicative form of fail at life