Synonyms of foolproof in English:

foolproof


See definition of foolproof

adjective

1‘we need a foolproof security system’

SYNONYMS
infallible, never failing, unfailing, unerring, dependable, reliable, trustworthy, certain, sure, guaranteed, safe, sound, effective, efficacious, tried and tested
watertight, airtight, flawless, perfect
informal sure-fire
ANTONYMS

flawed