penitent
词根词缀：
impunity n. 不受惩罚
im 不 + pun 惩罚 + ity 具备某种性质，状况 → 不受惩罚
penal adj. 刑罚的
pen 惩罚 + al …的 → 刑罚的
penalize v. 处罚
penal〔= pen〕惩罚 + ize 使 → 处罚
penalty n. 惩罚
penal 刑罚的 + ty 表情况 → 惩罚
penance n. 赎罪
pen 惩罚 + ance 表状况 → 接受惩罚 → 赎罪
penitent adj. 后悔的
penit〔= pen〕惩罚 + ent 具有…性质的，关于…的 → 因受惩罚而后悔 → 后悔的
punish v. 惩罚
pun 惩罚 + ish 使… → 惩罚
punishment n. 惩罚
punish 惩罚 + ment 表结果 → 惩罚
repent v. 后悔
re 反 + pent〔= pen〕惩罚 → 反过来惩罚自己 → 后悔
数据来源：新东方英语词汇速记大全
相关例句：
It was hard to be angrg with him when he looked so penitent.
当他看起来如此懊悔时，很难对他发火。
A half-equipped little Knight she was, venturing to reconnoitre the mysterious city and dreaming wild dreams of some vague, far-off supremacy, which should make it prey and subject& the proper penitent, groveling at a woman's slipper.
她还只是一个装备不全的小骑士，正冒险出发去侦察神秘的大城市，梦想着某个遥远的将来她将征服这新世界，让那大城市俯首称臣，诚惶诚恐，跪倒在她的脚下。
Once, Hollywood required scandal-ridden stars to go away for a while& a penitent hiatus before they could enjoy redemption, their second acts.
过去，好莱坞要求劣迹斑斑的影星离开一段时间&他们被救赎前的悔过期，好莱坞的第二步是救赎。
They knew not what it was, they knew not where they were; but both of them, the man and the child, the penitent and the innocent, felt that they must kneel.
他们不知道那是什么，他们不知道自己是在什么地方，可是他们俩，老人和孩子，忏悔者和无罪者，都感到应当跪下。
Robert Gates sat before them, almost penitent about the past
罗伯特·盖茨坐在他们面前，对过去的事几乎无颜以对。
Laurie was standing by their mother with such a penitent face that Jo forgave him on the spot.
劳笠站在她们的母亲身边，羞愧满面，无地自容。裘马上原谅了他。