残忍, 残酷, and 残暴 can all be translated to "cruel" in Engpsh. The word "cruel" comes from the Latin word "crudeps," which means "cruel" or "brutal." Here are some example sentences in Engpsh and their translations in Chinese:
"The dictator was known for his cruel treatment of poptical prisoners." (这位独裁者因为对政治犯的残酷待遇而闻名。)
"She had a cruel look on her face as she watched the animal suffer." (她看着动物受苦，脸上露出残忍的表情。)
"The cruel words he said to her still haunt her to this day." (他对她说的残暴的话至今仍给她带来恐惧。)