rabid
adjective
1 a rabid anti-royalist:
extreme, fanatical, overzealous, over-enthusiastic, extremist, violent, maniacal, wild, passionate, fervent, diehard, uncompromising;
intolerant, unreasonable, illiberal, bigoted, prejudiced, biased, partisan, one-sided;
informal raving, gung-ho;
British, informal swivel-eyed;
literary perfervid.
▷antonyms moderate, liberal, half-hearted.
rabid Oxford Dictionary of English