Today&s Japanese Words:

戦争 (sen-sou): war

戦う (tataka-u): to battle, to fight 

争う (araso-u): to compete

紛争 (hun-sou): dispute (noun)

民族紛争 (min-zoku-hun-sou): tribal disputes

国境紛争 (ko-kkyou-hun-sou): borderline disputes

衝突 (syou-totsu): conflict

内戦 (nai-sen): civil war

市民戦争 (shi-min-sen-sou): civil war (emphasizing the civilian aspect of the war)