Marked by extreme and violent energy:
— Fierce fighting.

synonyms: ferocious, furious, savage.

Roget 861: courageous, brave; valiant, valorous; gallant, intrepid; spirited, spiritful^†; high-spirited, high-mettled^†; mettlesome, plucky; manly, manful; resolute; stout, stout-hearted; iron-hearted, lion-hearted; heart of oak; Penthesilean.    bold, bold-spirited; daring, audacious; fearless, dauntless, dreadless^†, aweless; undaunted, unappalled, undismayed, unawed, unblanched, unabashed, unalarmed, unflinching, unshrinking^†, unblanching^†, unapprehensive; confident, self-reliant; bold as a lion, bold as brass.    enterprising, adventurous; venturous, venturesome; dashing, chivalrous; soldierly etc. (warlike) 722; heroic.    fierce, savage; pugnacious etc. (bellicose) 720.    strong-minded, hardy, doughty; firm etc. (stable) 150; determined etc. (resolved) 604; dogged, indomitable etc. (persevering) 604.1. up to, up to the scratch; upon one's mettle; reassured etc. v.; unfeared^†, undreaded^†.    ... show more

Roget 173: violent, vehement; warm; acute, sharp; rough, rude, ungentle, bluff, boisterous, wild; brusque, abrupt, waspish; impetuous; rampant.    turbulent; disorderly; blustering, raging etc. v.; troublous^†, riotous; tumultuary^†, tumultuous; obstreperous, uproarious; extravagant; unmitigated; ravening, inextinguishable, tameless; frenzied etc. (insane) 503.    desperate etc. (rash) 863; infuriate, furious, outrageous, frantic, hysteric, in hysterics.    fiery, flaming, scorching, hot, red-hot, ebullient.    savage, fierce, ferocious, fierce as a tiger.    excited etc. v.; unquelled^†, unquenched, unextinguished^†, unrepressed, unbridled, unruly; headstrong, ungovernable, unappeasable, immitigable, unmitigable^†; uncontrollable, incontrollable^†; insuppressible, irrepressible; orgastic, orgasmatic, orgasmic.    spasmodic, convulsive, explosive; detonating etc. v.; volcanic, meteoric; stormy etc. (wind) 349.    ... show more

Roget 900: angry, wrath, irate; ireful, wrathful; cross etc. (irascible) 901; Achillean^†; sulky, etc. 901.1; bitter, virulent; acrimonious etc. (discourteous) etc. 895; violent etc. 173.    warm, burning; boiling, boiling over; fuming, raging; foaming, foaming at the mouth; convulsed with rage.    offended etc. v.; waxy, acharne; wrought, worked up; indignant, hurt, sore; set against.    fierce, wild, rageful^†, furious, mad with rage, fiery, infuriate, rabid, savage; relentless etc. 919.    flushed with anger, flushed with rage; in a huff, in a stew, in a fume, in a pucker, in a passion, in a rage, in a fury, in a taking, in a way; on one's high ropes, up in arms; in high dudgeon.    ... show more

Marked by extreme intensity of emotions or convictions; inclined to react violently; fervid:
— Fierce loyalty.

synonyms: tearing, trigger-happy, vehement, violent.

Roget 825: excitable, easily excited, in an excitable state; high-strung; irritable etc. (irascible) 901; impatient, intolerant.    feverish, febrile, hysterical; delirious, mad, moody, maggoty-headed.    unquiet, mercurial, electric, galvanic, hasty, hurried, restless, fidgety, fussy; chafing etc. v.. startlish^†, mettlesome, high-mettled^†, skittish.    vehement, demonstrative, violent, wild, furious, fierce, fiery, hot-headed, madcap.    overzealous, enthusiastic, impassioned, fanatical; rabid etc. (eager) 865.    rampant, clamorous, uproarious, turbulent, tempestuous, tumultuary^†, boisterous.    impulsive, impetuous, passionate; uncontrolled, uncontrollable; ungovernable, irrepressible, stanchless^†, inextinguishable, burning, simmering, volcanic, ready to burst forth, volatile.    excited, exciting etc. 824.    ... show more

Ruthless in competition.

synonyms: bowelless, cutthroat.

Violently agitated and turbulent:
— The fierce thunders roar me their music.

synonyms: boisterous, rough.