One of the ancient Norse warriors legendary for working themselves into a frenzy before a battle and fighting with reckless savagery and insane fury.

synonym: berserker.

Roget 173: violence, inclemency, vehemence, might, impetuosity; boisterousness etc. adj.; effervescence, ebullition; turbulence, bluster; uproar, callithump [U.S.], riot, row, rumpus, le diable a quatre [Fr.], devil to pay, all the fat in the fire.    severity etc. 739; ferocity, rage, fury; exacerbation, exasperation, malignity; fit, paroxysm; orgasm, climax, aphrodisia^†; force, brute force; outrage; coup de main; strain, shock, shog^†; spasm, convulsion, throe; hysterics, passion etc. (state of excitability) 825.    outbreak, outburst; debacle; burst, bounce, dissilience^†, discharge, volley, explosion, blow up, blast, detonation, rush, eruption, displosion^†, torrent.    turmoil etc. (disorder) 59; ferment etc. (agitation) 315; storm, tempest, rough weather; squall etc. (wind) 349; earthquake, volcano, thunderstorm.    berserk, berserker; fury, dragon, demon, tiger, beldame, Tisiphone^†, Megaera, Alecto^†, madcap, wild beast; fire eater etc. (blusterer) 887.    ... show more

Dutch: berserker

Wildly frenzied and out of control:
— Berserk with grief.
— A berserk worker smashing windows.

synonyms: amok, amuck.

Roget 503: insane, mad, lunatic, loony [Coll.]; crazy, crazed, aliene^†, non compos mentis; not right, cracked, touched; bereft of reason; all possessed, unhinged, unsettled in one's mind; insensate, reasonless, beside oneself, demented, daft; phrenzied^†, frenzied, frenetic; possessed, possessed with a devil; deranged, maddened, moonstruck; shatterpated^†; mad-brained, scatter brained, shatter brained, crackbrained; touched, tetched [Coll.]; off one's head.    [behavior suggesting insanity] maniacal; delirious, lightheaded, incoherent, rambling, doting, wandering; frantic, raving, stark staring mad, stark raving mad, wild-eyed, berserk; delusional, hallucinatory.    [behavior somewhat resembling insanity] corybantic^†, dithyrambic; rabid, giddy, vertiginous, wild; haggard, mazed; flighty; distracted, distraught; depressed; agitated, hyped up; bewildered etc. (uncertain) 475.    mad as a March hare, mad as a hatter; of unsound mind etc. n.; touched in one's head, wrong in one's head, not right in one's head, not in one's right mind, not right in one's wits, upper story; out of one's mind, out of one's wits, out of one's skull [Coll.], far gone, out of one's senses, out of one's wits; not in one's right mind.    fanatical, infatuated, odd, eccentric; hypped^†, hyppish^†; spaced out [Coll.].    imbecile, silly, etc. 499.    ... show more