Synonyms for War:

n.

mission, skirmish, incursion, pitched battle. misunderstanding, disagreement, quarrel, race, striving, dispute, Corrivalry, tug-of-war, rivalry, controversy, strife, argument, a war of words, competition. Benedict Arnold, Auschwitz, the Bay of Pigs, confrontation, the Axis, allied, the Battle of Britain, the Allies, belligerency, armistice day, the Berlin Wall, antebellum. discord, dissonance, difference, Inharmony, contention, schism, heavy lifting, work, clash, difficulty, pursuit, exertion, care, effort, variance, undertaking, strain, dedication, disaccord, dissension, friction, faction, challenge, dissentience, dissidence, dissent, discordance. contend, wrestle, duel, free-for-all, tilt. act (noun)
warfare.
armed conflict (noun)
conflict, strike, fighting, battle, contention, struggle, strife, bloodshed, hostility, contest, Hostilities, combat, warfare.
attack (noun)
barrage, charge, riot, spasm, assault, raid, fury, foray, furor, battle, combat, storm, bloodshed, strike, warfare, thrust, attack, onslaught, siege, sortie, invasion, outbreak, tirade, offense, violence, fight, bombardment, frenzy, aggression.
battle (noun)
strife, combat, sortie.
competition (noun)
contention.
conflict (noun)
dissentience, discordance, tug-of-war.
discordance (noun)
Inharmony.
war (noun)
state of war, warfare.
warfare (noun)
drive, contest, engagement, scuffle, jihad, tussle, crusade, hostility, struggle, warpath, scramble, guerre, campaign, conflict, offensive.

v.

conflict (verb)
world, revolutionary, naval, total, fighting, nuclear, land, religious, trench, biological, limited, amphibious, push button, Hostilities, three-dimensional, political, civil, blitzkrieg, bacteriological, atomic, psychological, guerrilla, hot, atomic-bacteriological-chemical, aerial, shooting, war to end all wars, chemical, holy war, preventive, ground, armageddon, germ, sea, cold, defensive, war of nerves.
fight, battle (verb)
challenge, clash, attack, contend.

Other synonyms:

incursion, pitched battle, skirmish, discordance, dissentience, Corrivalry, Inharmony, amphibious, tug-of-war, belligerency. contend, duel, striving, dissonance, mission, dissidence, dissension, rivalry, friction. schism, confrontation, strife, variance, wrestle, disaccord. discord, competition, faction, race, tilt, contention. difference, difficulty. disagree
quarrel.

Usage examples for war

  1. But if ye're goin' to cry, Deely, why, I want for to stop ye; and I do think it war all right, your leavin' me." – True and Other Stories by George Parsons Lathrop
  2. What will happen before the war is over is another matter. – A Journey Through France in War Time by Joseph G. Butler, Jr.
  3. War there, my son? – Queen Mary and Harold by Alfred Lord Tennyson