Synonyms of infallible in English:

infallible


See US English definition of infallible

See UK English definition of infallible

See Spanish definition of infalible

adjective

1‘she had an infallible sense of timing’

SYNONYMS
unerring, error-free, unfailing, faultless, flawless, impeccable, perfect, true, uncanny, precise, accurate, meticulous, scrupulous
British informal spot on
North American informal on the money

2‘infallible cures for a variety of ailments’

SYNONYMS
unfailing, never failing, always effective, guaranteed, dependable, trustworthy, reliable, sure, certain, safe, sound, tried and tested, foolproof, effective, efficacious
informal sure-fire