Euphemism

the substitution of an agreeable or inoffensive expression for one that may offend or suggest something unpleasant; also : the expression so substituted

Example sentence:
Aunt Helen would never say that someone had "died"; she preferred to communicate the unpleasant news with euphemisms like "passed on."

Did you know?
"Euphemism" derives from the Greek word "euphēmos," which means "auspicious" or "sounding good." The first part of "euphēmos" is the Greek prefix "eu-," meaning "well." The second part is "phēmē," a Greek word for "speech" that is itself a derivative of the verb "phanai," meaning "to speak." Among the numerous linguistic cousins of "euphemism" on the "eu-" side of the family are "eulogy," "euphoria," and "euthanasia"; on the "phanai" side, its kin include "prophet" and "aphasia" ("loss of the power to understand words").

委婉語，英文叫Euphemism。 (文章允許轉貼，請具作者名字：梁煥松)
越發展得成熟的文化，豐富多彩的語言，委婉語必定越多。就是因為種種的原因，不把意思講明白，而要用另一個含蓄的說法。中文的委婉語 ，一說出來，大家必會說：哦！我明白啦！ 例如中國人很怕把「死」字直接講出來，於是有「去世」、「逝世」、「仙遊」、「往生」、「歸西」，廣東話有「去左」、「過身」、「唔係度」等等。
又如不想把某些形容詞直接講出來，恐怕使人難受，如：
把「盲」說成「失明」；把「聾」說成「失聰」；把「跛」說成「不良於行」； 或近年大陸把「失業」說為「下崗」等等。英文中也有很多的委婉語(Euphemism)，尤其是近年的講究Non-discriminatory(不帶歧視色彩) 的語言，經過傳媒和廣告撰稿人的加鹽加醋，以及注重政治正確(Political Correctness)的公務人員的「潤色」，更是五花八門，例如：

形容聾人，不說Deaf，說Hearing-impaired (聽覺有障礙)；形容窮人，不說Poor，說Disadvantaged (得不到好處)；形容二手貨，不說Second-hand ，說 Pre-loved(曾經有人愛過)；形容性別，不說Sex(男性、女性的「性」)，說 Gender(文法中，名詞的陽性和陰性「性」)；形容貨品便宜，不說Cheap(使購買者「自我感覺不好」)，說 Affordable(易於負擔)等等。

但我覺得有時做得太過份了！請看一個Lame(跛)字，越說越隱晦和累贅，有以下的「發展史」：lame → crippled → handicapped → disabled → differently-abled
最後一個differently-abled，簡直是爛英文之尤。

有關委婉語，可參考下面的詳細資料：