Verb (1-dan, intransitive)
1. to be disordered; to be disarranged; to be disarrayed; to be disheveled; to be dishevelled
ふと鏡を見た時、自分の姿の乱れように気がついた。When I happened to look in the mirror, I noticed how disheveled my appearance was.
2. to be discomposed; to be upset; to get confused; to be disturbed
なのに全然落ち着かなくてむしろ気持ちが乱れていく。And yet, I can't calm down at all; rather, my feelings are becoming more disturbed.
3. to lapse into chaos (due to war, etc.)
その時代、世の中は乱れていた。In those days, society was in chaos.