bad

将“bad”想象成一个人的表情很糟糕，或者心里有不好的想法，通过这种视觉联想帮助记忆单词的含义为“糟糕的、不好的”。

bad 坏的

词源同boar, 野猪。古义指狂野的，邪恶的。

bad

bad: [13] For such a common word, bad has a remarkably clouded history. It does not begin to appear in English until the end of the 13th century, and has no apparent relatives in other languages (the uncanny resemblance to Persian bad is purely coincidental). The few clues we have suggest a regrettably homophobic origin. Old English had a pair of words, bǣddel and bǣdling, which appear to have been derogatory terms for homosexuals, with overtones of sodomy.

The fact that the first examples we have of bad, from the late 13th and early 14th centuries, are in the sense ‘contemptible, worthless’ as applied to people indicates that the connotations of moral depravity may have become generalized from an earlier, specifically anti-homosexual sense.

bad (adj.)

c. 1200, "inferior in quality;" early 13c., "wicked, evil, vicious," a mystery word with no apparent relatives in other languages.* Possibly from Old English derogatory term bæddel and its diminutive bædling "effeminate man, hermaphrodite, pederast," probably related to bædan "to defile." A rare word before 1400, and evil was more common in this sense until c. 1700. Meaning "uncomfortable, sorry" is 1839, American English colloquial.

Comparable words in the other Indo-European languages tend to have grown from descriptions of specific qualities, such as "ugly," "defective," "weak," "faithless," "impudent," "crooked," "filthy" (such as Greek kakos, probably from the word for "excrement;" Russian plochoj, related to Old Church Slavonic plachu "wavering, timid;" Persian gast, Old Persian gasta-, related to gand "stench;" German schlecht, originally "level, straight, smooth," whence "simple, ordinary," then "bad").

Comparative and superlative forms badder, baddest were common 14c.-18c. and used as recently as Defoe (but not by Shakespeare), but yielded to comparative worse and superlative worst (which had belonged to evil and ill).

As a noun, late 14c., "evil, wickedness." In U.S. place names, sometimes translating native terms meaning "supernaturally dangerous." Ironic use as a word of approval is said to be at least since 1890s orally, originally in Black English, emerging in print 1928 in a jazz context. It might have emerged from the ambivalence of expressions like bad nigger, used as a term of reproach by whites, but among blacks sometimes representing one who stood up to injustice, but in the U.S. West bad man also had a certain ambivalence:

These are the men who do most of the killing in frontier communities, yet it is a noteworthy fact that the men who are killed generally deserve their fate. [Farmer & Henley]

*Farsi has bad in more or less the same sense as the English word, but this is regarded by linguists as a coincidence. The forms of the words diverge as they are traced back in time (Farsi bad comes from Middle Persian vat), and such accidental convergences exist across many languages, given the vast number of words in each and the limited range of sounds humans can make to signify them. Among other coincidental matches with English are Korean mani "many," Chinese pei "pay," Nahuatl (Aztecan) huel "well," Maya hol "hole."

1. If you're lonely when you're alone, you're in bad company.--Jean Paul Sartre

如果你独处时感到寂寞，说明没有把自己陪好。

2. Too bad he used his intelligence for criminal purposes.

他把聪明都用在了犯罪上，太可惜了。

3. When the right woman comes along, this bad dream will be over.

当有合适的女人出现时，这种胡思乱想就会停止了。

4. She was in rather a bad film about the Mau Mau.

她出演了一部关于茅茅运动（20世纪50年代肯尼亚基库尤人反抗英国殖民者的民族主义运动）的烂片。

5. Many parents find it hard to discourage bad behaviour.

很多父母觉得要孩子循规蹈矩是件很难的事情。

【ill, poor, bad, evil, wicked】
这组词都有“坏的”的意思，其区别是：
ill: 与evil意义接近，但语气弱一些，常指道德或性质方面的不良。
poor: 普通用词，侧重指事物的质量或数量低于标准或不合要求。用于指天气与食品时可与bad通用。
bad: 含义广泛，指任何不好的或不合需要的品质。
evil: 语气比bad强，强调道德上的邪恶不良，含狡猾凶险或危害他人的意味。
wicked: 语气比evil强，指居心叵测，任意违反道德标准，有意作恶。

【badly, bad】
badly: 副词,不好,但与need, want, require连用为"很,非常" I need the book badly.
bad: 形容词, go bad