Not To Be Confused With
Two distinct uses: (1) Scripture's infallibility (it cannot fail in what it teaches for salvation); (2) papal/Church infallibility — a specifically Catholic claim that the Magisterium is preserved from error when defining doctrine. Don't conflate them.
Of Scripture, infallibility means it will not lead astray in what it teaches. Of the Church, the First Vatican Council (1870) defined that the pope teaches infallibly under strict conditions (ex cathedra, on faith or morals) — a claim Orthodox and Protestants reject, bound up with the authority debate.