I. ˈ ̷ ̷ ˌ ̷ ̷ adjective
Etymology: fail (I) + safe (I)
1. : incorporating some feature for automatically counteracting the effect of an anticipated possible source of failure
2. : being or relating to a safeguard that prevents continuing on a bombing mission according to a preconceived plan
3. : having no chance of failure : infallibly problem-free
a written guarantee that your back is in A-1, fail-safe condition — Fern Lebo
II. " intransitive verb
: to counteract the effect of a malfunction automatically
transitive verb
: to equip with a fail-safe device