Synonyms|44Antonyms|8|Broader|1Narrower|0Related|96
6
foolproof(adjective, fail, thrive, infallible)
4
reliable(adjective, fail)
4
secure(adjective, fail)
4
sound(adjective, fail)
3
sure(adjective, fail)
2
guaranteed
1
certain
1
covered(adjective, fail)
1
dependable
1
firm
1
harmless
1
invulnerable
1
protected(adjective, fail)
1
safe
1
stable
1
steady
1
trustworthy
0
analog
0
automatic
0
automatically
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APASmart Define. (2015). fail-safe thesaurus. Retrieved September 20, 2026, from https://smartdefine.org/fail-safe/thesaurus/synonyms
ChicagoSmart Define. 2015. "fail-safe thesaurus" https://smartdefine.org/fail-safe/thesaurus/synonyms (accessed September 20, 2026).
HarvardSmart Define 2015, fail-safe thesaurus, Smart Define, viewed 20 September, 2026, <https://smartdefine.org/fail-safe/thesaurus/synonyms>.
MLASmart Define. "fail-safe thesaurus" 14 April 2015. Web. 20 September 2026. <https://smartdefine.org/fail-safe/thesaurus/synonyms>