Synonyms of diehard in English:

diehard


See US English definition of diehard

See UK English definition of diehard

See Spanish definition of intransigente

adjective

1‘diehard traditionalists’

SYNONYMS
hard-line, hardcore, reactionary, ultra-conservative, conservative, traditionalist, unprogressive, dyed-in-the-wool, deep-dyed, long-standing, staunch, steadfast, intransigent, inflexible, immovable, unchanging, uncompromising, unyielding, indomitable, adamant, rigid, entrenched, set in one's ways
informal blimpish
British true-blue

noun

1‘some of the diehards are refusing to reach an agreement’

SYNONYMS
hardliner, reactionary, ultra-conservative, conservative, traditionalist, intransigent
fanatic, zealot
British true blue
informal, derogatory stick-in-the-mud
British informal, derogatory gammon, blimp
ANTONYMS

modernizer