See die-hard in Webster's New World Roget's A-Z Thesaurus II
also
diehard adjective
Firmly, often unreasonably immovable in purpose or will:
adamant, adamantine, brassbound, grim, implacable, incompliant, inexorable, inflexible, intransigent, iron, obdurate, relentless, remorseless, rigid, stubborn, unbendable, unbending, uncompliant, uncompromising, unrelenting, unyielding. Idiom: stubborn as a mule (or ox). See resistVehemently, often fanatically opposing progress or reform:
mossbacked, reactionary, ultraconservative. See politics
noun
A person who vehemently, often fanatically opposes progress and favors return to a previous condition:
mossback, reactionary, ultraconservative. See politics
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