Source : WordNet®

rock-ribbed
     adj 1: abounding in or bordered by rocky cliffs or scarps; "the
            rock-ribbed coast of Maine" [syn: {rockbound}]
     2: tradition-bound and obstinately opinionated; "an inflexible
        (or die-hard) conservative"; "rock-ribbed republican"
        [syn: {die-hard(a)}]