Foolproof
Foolproof adjective - Not liable to failure.
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Synonyms for Foolproof
Sound and foolproof are semantically related. in infallible topic. In some cases you can use "Sound" instead an adjective "Foolproof".
Sound
Sound adjective - According to the rules of logic.
Mutual synonyms
Both words in one sentence
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Given the difficulty of hitting a relatively small target hurtling toward you at multiple times the speed of sound in the few seconds between when you can first detect it and when it hits you, even modern anti-missile systems are far from foolproof, though they certainly aren't useless.
Source: Point Defenseless -
This plan may sound foolproof, but it has one flaw: the jai alai player just happens to be insured by Lloyd's of London for half a million dollars.
Source: Film / Wonder Women
Cite this Source
Sound and Foolproof. (2016). Retrieved 2026, August 15, from https://thesaurus.plus/related/foolproof/sound
Foolproof & Sound. N.p., 2016. Web. 15 Aug. 2026. <https://thesaurus.plus/related/foolproof/sound>.
Sound or Foolproof. 2016. Accessed August 15, 2026. https://thesaurus.plus/related/foolproof/sound.
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