the GNU version of the Collaborative International Dictionary of English
adj. Committing no mistake; incapable or error or failure certain; sure; unfailing.
The Century Dictionary and Cyclopedia
Not missing the mark; certain: as, an unerring aim.
Committing no mistake; incapable of error; infallible: as, the unerring wisdom of God.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
adj. not liable to error
Word Usage
"What it has been the fashion to call their unerring instinct is after all infallible only as a certain great public functionary is, -- in theory; and their mistaken haste is too frequently nothing but a hurrying to their death."