1. 战争行为：hostile 怀敌意 | hostilities 战争行为 | hostlerostler 旅馆的马夫

2. hostilities

2. 双方敌意：civil war内战 | hostilities双方敌意 | revolution革命

3. 敌对行动：hostile operations;敌对行动;; | hostilities;敌对行动;; | hot cells;热室;;

4. 战争：劫持人质hostage-taking | 战争hostilities | 敌对行为hostility

1. 战争行动
    You can refer to fighting between two countries or groups who are at war as hostilities .

hostilities

    e.g. The authorities have urged people to stock up on fuel in case hostilities break out.
           当局已敦促人们储存燃料，以防战事爆发。

1. fighting
    acts of overt warfare

    e.g. the outbreak of hostilities

    Synonym: belligerency