**The phrase used here, 霸王硬上弓, means forcefully doing something; nowadays, the meaning of the word has extended to mean rape (forcefully conducting a sexual act). The author described the nickname as vulgar, so it's been translated as rape. The origin behind the phrase is pretty interesting. Legends have it that Xiang Yu the Conqueror*** was someone with boundless strength. Back then, people had to use their feet to draw the bowstring back, but he could forcefully draw the bowstring with just his arms. Hence, 霸王硬上弓 literally means Xiang Yu forcefully pulls back the bowstring.
***I just googled him and it turns out this dude's actually super famous.