fanatic, zealous, obsessed, impassioned, passionate, rabid, extreme, extremist, bigoted, devoted, feverish, prejudiced, biased, radical, militant, immoderate, partisan, obstinate, headstrong, burning, fiery, fervent, fervid, ardent, frenzied, excessively enthusiastic, overzealous, overenthusiastic, raving, of the lunatic fringe, maniacal, mad, wild, partial, stubborn, singleminded, one-ideaed, monomaniacal, infatuated, possessed, opinionated, narrow-minded, dogmatic, arbitrary, positive, tenacious, die-hard, ultraist, hard-line, wild-eyed.
Antonyms moderate*, reasonable, impartial.
