Noun and する verb
せんそう
戦争に行くのは半年ぶりです。
This is the first time I've gone to war in six months.
戦争をしない方がいい理由を十こあげてください。
Can you list up to ten reasons why we shouldn't go to war?
戦争が始まる前に、腹筋を六つに割りたい。
I want to get a six pack before the war begins.
You have war and conflict. Of course, conflict comes with war, so this word just means war.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.