infallible
adj.
early 15c., from Medieval Latin infallibilis, from in- "not, opposite of" (see in-(1)) + Late Latin fallibilis (see fallible). In reference to Popes, attested from 1870. Related: Infallibly.
〔李〕[in-=not 不；fallible a.易犯错误的→] a. free from error 不会犯错误的，无过失的
〔李〕[in-;fall;-iblea.] a.没有错误的，确实可靠的 ←fall,fals (L fallere,falsum)=to deceive 骗