The word "兵荒马乱" is formed by combining two parallel phrases: "兵荒", meaning soldiers are in disarray, and "马乱", meaning horses are in chaos. Each phrase pairs a noun (兵 for soldiers, 马 for horses) with a descriptive character indicating disorder (荒 for desolation or disarray, 乱 for chaos). Together, these components create a compound idiom that vividly depicts the turmoil and devastation of war through the imagery of military and cavalry in a state of extreme confusion.