fanatical

Synonyms: biased bigoted bugged burning contumacious credulous devoted dogmatic domineering enthusiastic erratic extreme fervent feverish fiery frenzied headstrong high on immoderate impassioned impulsive incorrigible infatuated mad monomaniacal narrow-minded nuts for obsessed obsessive obstinate opinionated partial partisan passionate possessed prejudiced rabid radical raving single-minded stubborn turned on unruly violent visionary wild willful zealous

Antonyms: disinterested dispassionate impartial unenthusiastic