Foolproof

Adjective

 * 1) For a device: protected, or designed to be proof against misuse or error; fail-safe.
 * 2) For an idea or plan: infallible, or bulletproof.

Thesaurus
adaptable, airtight, ballproof, bombproof, bulletproof, burglarproof, certain, convenient, corrosionproof, dampproof, dependable, ductile, feasible, fire-resisting, fireproof, flameproof, flexible, guaranteed, handy, hermetic, holeproof, impervious to, infallible, leakproof, malleable, manageable, maneuverable, noiseproof, pliable, pliant, practical, proof, proof against, punctureproof, reliable, resistant, rustproof, safe, shatterproof, shellproof, soundproof, sure, sure-fire, tight, tractable, trustworthy, unfailing, untroublesome, warranted, watertight, weatherproof, wieldable, wieldy, yielding

Translations

 * German: narrensicher, idiotensicher
 * Spanish:


 * Swedish:


 * Spanish: