bad / bad/ • adj. (worse / wərs/ ; worst / wərst/ ) 1. of poor quality; inferior or defective: a bad diet. ∎  (of a person) not able to do something well; incompetent: I'm so bad at names.2. unpleasant or unwelcome: bad news. ∎  unsatisfactory or unfortunate: bad luck | [as n.] (the bad) taking the good with the bad. ∎  (of an unwelcome thing) serious; severe: bad headaches a bad mistake. ∎  unfavorable; adverse: bad reviews. ∎  harmful: soap was bad for his face. ∎  not suitable: morning was a bad time to ask Andy about anything.3. (of food) decayed; putrid: everything in the fridge would go bad. ∎  (of the atmosphere) polluted; unhealthy: bad air.4. (of parts of the body) injured, diseased, or causing pain: a bad back. ∎  (of a person) unwell: I feel bad.5. regretful, guilty, or ashamed about something: working mothers who feel bad about leaving their children.6. morally depraved; wicked: the bad guys bad language a bad reputation. ∎  naughty; badly behaved: what a bad girl.7. worthless; not valid: he ran up 87 bad checks.8. (bad·der, bad·dest) inf. good; excellent: they want the baddest, best-looking Corvette there is.• adv. inf. badly: he beat her up real bad.PHRASES: in a bad way ill: Sammy shivered. He was in a bad way. ∎  in trouble.not (or not so) bad inf. fairly good: she discovered he wasn't so bad after all.too bad inf. used to indicate that something is regrettable but now beyond retrieval: too bad, but that's the way it is.DERIVATIVES: bad·dish adj.bad·ness n.

bad a bad excuse is better than none it is better to attempt to give some kind of explanation, even a weak one; proverbial saying recorded from the mid 16th century.
bad hair day a day on which everything seems to go wrong, characterized as a day on which one's hair is particularly unmanageable; an expression which became current in the 1990s.
bad money drives out good money of lower intrinsic value tends to circulate more freely than money of higher intrinsic and equal nominal value, through what is recognized as money of higher value being hoarded. It is known as Gresham's law after Sir Thomas Gresham (c.1519–79), founder of the Royal Exchange. Gresham saw the economic need to restore the purity of the coinage, though there is no evidence that he actually used this expression. The saying in this form is recorded from the early 20th century.
bad news travels fast bad news is more likely to be talked about than good news. This saying is recorded from the late 16th century; a mid 16th-century translation of Erasmus's Adages has the related ‘Sad and heavy tidings be easily blown abroad be they never so vain and false and they be also soon believed.’
a bad penny always turns up the return of an unwanted or disreputable person is inevitable; proverbial saying from the mid 18th century.
bad things come in threes the belief that an accident or misfortune is likely to be accompanied by two more is a well-attested traditional belief, although in this form it is only recorded from the late 20th century.
a bad workman blames his tools often used as a comment on someone's excuses for their lack of success. Proverbial saying recorded from the early 17th century in English, and the late 13th century in French.
there is no such thing as bad weather, only the wrong clothes modern saying, recorded from the late 20th century, which attributes suffering from the prevailing temperature or other weather conditions to a person's lack of preparedness and good sense.

bad XIII (first applied to worthless or contemptible persons). ME. badde, perh. repr. OE. bæddel hermaphrodite (Cf. bædling sodomite) with loss of l as in MUCH, WENCH.

Bad

A jinni (or genie) of Persia (modern-day Iran), supposed to have command over the winds and tempests. He presided over the twenty-second day of the month.

BAD base air depot
• British Association of Dermatology