词根：rad, ras(raz) = to rub, to scrape（刮擦）
来源于拉丁语 radere 意为to rub, to scrape 刮擦。其变形为raz，ras。
同源词：
1. erase
v.擦掉 *e<ex(=out)
erasure n.抹去；擦掉 [-ure抽象名词后缀]
2. eraser
n.擦除器（如橡皮、黑板擦等）*e<ex(=out)
3. rase/raze
v.拆毁，夷平
city razed by an earthquake 被地震夷为平地的城市
4. abrasive [ab(=away) ras/rad(=scrape)] 刮擦以使脱离、消失
adj. causing abrasion ;harsh,rough 磨擦的，磨损的；使和别人产生摩擦的；烦人的，恼人的；粗糙的；
n.substance used for rubbing or grinding down surfaces 磨料
abrasiveness n. 与人关系上的摩擦；
abrasion n.磨损，磨耗；
The texture of a cat's tongue is remarkably abrasive.猫的舌头异常粗糙。
5. rascal
n.恶棍；（开玩笑愚弄人的）捣蛋鬼
6. rascally
adj.流氓的，卑鄙的
rascally trick 卑劣的伎俩
7. rash
n.疹；短时间内爆发的一连串（多指不愉快的事物）adj.急躁的；鲁莽的，轻率的
heat-rash 痱子
come out in a rash 身上生满疹子
rash act 草率的行动
rash young man 鲁莽的年轻人
8. rasp
n.粗锉刀；锉磨声
v.用粗锉刀锉；刺激，使恼怒；发出刮攘声；发出刺耳的声音；用嘶哑的声音大声说
rasp one's feelings/nerves 刺激某人的感情，神经
rasp out orders 用嘶哑的声音大声命令
rasping voice 刺耳的囔音
9. razor
n.剃刀；刮须刀
10. raze
v.（从记忆中）消逝；忘却；摧毁
词根：dulg = to yield
来自拉丁语的dulg意为to yield。
indulgent （向某人让步的in (=to) + dulg (=yield)）
adj.纵容的；宽容的
indulge v.沉迷，沉溺于；纵容；使自己高兴一下
indulgence n.纵容，放纵；宽容；沉溺
She was a harsh mother but is an indulgent grandmother.她是一个严厉的母亲，不过却是一个宽容的祖母。
词根：acerb = bitter, harsh
词根acerb来自拉丁语的acerb意为bitter,barsh。
同源词：
1. exacerbate vi.使痛苦、疾病等）恶化；激怒 （使非常痛苦或难受 ex(=intensive) + acerb(=bitter,harsh)）
exacerbation 恶化；激怒
Many study shows that stress and tension can exacerbate pain.很多研究表明压力和紧张会加剧疼痛。
2. acerbity n.尖酸；酸，苦，辣
词根词缀：auster-
【来源及含义】Greek: austeros, harsh, rough, bitter > Latin: dry, harsh, sour, tart
【同源单词】anti-austerity protest, austere, austerely, austereness, austerity, austerity
词根词缀：caco-, cac-, kako-, kak-
【来源及含义】Greek: bad, harsh, wrong, evil; incorrect; unpleasant; poor; used most of the time as a prefix
【相关词根词缀】Inter-related cross references, directly or indirectly, involving word units meaning "bad, wrong": dys-; mal-; mis-; pessim-; sceler-.
【同源单词】alexicacon, cacaerometer, cacaesthesia, cacergasia, cachectic, cachexia
词根词缀：dys-
【来源及含义】Greek: bad, harsh, wrong; ill; hard to do, difficult at; slow of; disordered; impaired, defective
【相关词根词缀】Inter-related cross references, directly or indirectly, involving word units meaning "bad, wrong": caco-, kako-; mal-; mis-; pessim-; sceler-. Cross references directly, or indirectly, involving "slow, slowness, slow of, sluggish": lent-; tard-.
【同源单词】acrodysaesthesia, acrodysostosis, algesidystrophy, algodystrophy, amebic dysentery, amylodyspepsia
词根词缀：mal-, male-, mali-
【来源及含义】Latin: bad, badly, harsh, wrong; ill; evil; abnormal, defective; used primarily as a prefix
【相关描述】This combining form has no etymological connection to "male", meaning "man" or "masculine"; despite what some women may think.
【相关词根词缀】Inter-related cross references, directly or indirectly, involving word units meaning "bad, wrong": caco-, kako-; dys-; mis-; pessim-; sceler-.
【同源单词】benediction, benevolence, grand mal seizure, mala fide, mala fide, Mala ultro adsunt
词根词缀：mis-
【来源及含义】Anglo-Saxon: bad, harsh, wrong; always a prefix
【相关描述】Don't confuse this mis- unit with the following units: misce-, "mix, mingle"; miso-, mis-, "hate, hatred"; miss-, -miss, -mis- "send, throw".
【相关词根词缀】Inter-related cross references, directly or indirectly, involving word units meaning "bad, wrong": caco-, kako-; dys-; mal-; pessim-; sceler-.
【同源单词】misadventure, misbegotten, misbehave, misbehavior, miscall, mischief
词根词缀：rauc-
【来源及含义】Latin: "hoarse"; hoarse cries; howl, roar; rough-sounding, harsh; loud, rough
【同源单词】raucity, raucous, raucously, raucousness
词根词缀：stridu-, strid-
【来源及含义】Latin: creaking, making a creaking sound; a shrill sound; a harsh sound
【同源单词】laryngismus stridulus, laryngitis stridulosa, strident, stridor, stridulant, stridulate