hind leg; hind foot
犬が後ろ足で立ち上がった。
The dog stood up on its hind legs.
猫は棚から落ちて後ろ足を怪我した。
The cat fell from the shelf and injured its hind leg.
彼は世話になった上司に後ろ足で砂をかけて辞職した。
He ungratefully turned his back on the boss who had mentored him and resigned.