A confrontation is an angry disagreement. You might become so irritated about your upstairs neighbor's loud, awful music that a confrontation is unavoidable.
Confrontation implies hostility, although like a fight, a confrontation can involve actual violence, or just a clash of words. A confrontation often refers to a military encounter involving opposing armies. This meaning became popular after the Cuban missile crisis in 1963. Before that, confrontation was used to mean "bringing two opposing parties face to face," from the Latin word confrontationem.