a. [ L. impeccabilis; pref. im- not + peccare to err, to sin: cf. F. impeccable. ] Not liable to sin; exempt from the possibility of doing wrong. -- n. One who is impeccable; esp., one of a sect of Gnostic heretics who asserted their sinlessness. [ 1913 Webster ]
God is infallible, impeccable, and absolutely perfect. P. Skelton. [ 1913 Webster ]