出典:Wiktionary
A horse is roughshod if its hooves are shod with horseshoes that have calks (projecting parts to prevent slipping). Thus, something that a roughshod horse is ridden over is likely to be damaged by the projections of its horseshoes.[1]
ride roughshod over (三人称単数 現在形 rides roughshod over, 現在分詞 riding roughshod over, 過去形 rode roughshod over, 過去分詞 ridden roughshod over)