FIDEISM Meaning of FIDEISM in English [ 'fʌɪdɪɪz(ə)m ]■ noun the doctrine that knowledge depends on faith or revelation.Derivativesfideist nounfideistic adjective OriginC19: from L. fides 'faith' + -ism . Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004