一心不乱[isshinfuran] wholeheartedly
淫乱[inran] debauched
潰乱[kairan] corruption (of order, customs, etc.)
快刀乱麻[kaitouranma] solving a problem swiftly and skillfully
怪力乱神[kairyokuranshin] supernatural things

外乱[gairan] noise (interference)
狂乱[kyouran] fury
胡乱[uron] suspicious looking
混乱[konran] disorder
咲乱れる[sakimidareru] to bloom in profusion

ガリア戦記[gariasenki] History of the Gallic Wars
ゲリラ戦[gerirasen] guerrilla warfare
セールス戦略[seerususenryaku] sales strategy
ベトナム戦争[betonamusensou] Vietnam war
マーケティング戦略[maaketingusenryaku] marketing strategy

悪戦[akusen] hard fighting
悪戦苦闘[akusenkutou] hard fighting
一回戦[ikkaisen] first game
一戦[issen] battle
厭戦[ensen] war weariness