From Longman Dictionary of Contemporary Englishdieharddie‧hard /ˈdaɪhɑːd $ -hɑːrd/ noun [countable] CHANGE YOUR MINDEXTREMEsomeone who opposes change and refuses to accept new ideas —diehard adjective a few diehard fans → old habits die hard at die1(10)
Examples from the Corpus
diehard• How could he make them see there was nothing to his scheme but the marginal notes of a diehard and fool?• His proclamation that the moon might be habitable was bound to attract criticism from Aristotelian diehards such as Alexander Ross.• Todd Tiahrt is second to none among Gingrichite diehards in his zeal to cut tax.• The staff writers seem to be a conglomeration of music diehards steeped in the traditions of classic rock.• Nearly all the collectable money is now in; only a small number of diehards continue to withhold cash.• Salisbury, Walton, and a few other diehards still refused to join the coalition.• Lansdowne was more exposed to the views of the real diehards and was thus a restraining influence on Law.• Taylor is one of the diehards willing to push the development program at any price.• Apart from a few union diehards most of the men have accepted the new productivity agreement.