Error, mistake.

An item (or kind of item) of merchandise with negative value; an unwanted good.

Unfavorable; negative; not good.

"Abducting children is bad for mothers."

Not suitable or fitting.

"Do you think it is a bad idea to confront him directly?"

Not appropriate, of manners etc.

"It is bad manners to talk with your mouth full."

Unhealthy; liable to cause health problems.

"Lard is bad for you. Smoking is bad for you, too. Grapes are bad for dogs but not for humans."

Sickly, unhealthy, unwell.

"I went to the hospital to see how my grandfather was doing. Unfortunately, he's in a bad state."

Not behaving; behaving badly; misbehaving; mischievous or disobedient.

"Stop being bad, or you will get a spanking!"

Tricky; stressful; unpleasant.

"Divorce is usually a bad experience for everybody involved."

Evil; wicked.

"Be careful. There are bad people in the world."

Faulty; not functional.

"I had a bad headlight."

(of food) Spoiled, rotten, overripe.

"These apples have gone bad."

(of breath) Malodorous; foul.

"Bad breath is not pleasant for anyone."

False; counterfeit; illegitimate.

"They were caught trying to pass bad coinage."

Unskilled; of limited ability; not good.

"He's a bad gardener; everything he tries to grow ends up dying."

Of poor physical appearance.

"I don't look bad in this dress, do I?"

Bold and daring.

Good, superlative, excellent, cool.

"Man, that new car you bought is bad!"

(of a need, want, or pain) Severe, urgent.

"He is in bad need of a haircut."

Overly promiscuous, licentious.

(of a draft/check) Not covered by funds on account.

"He gave me a bad check."

Badly.

"I didn't do too bad in the last exam."

Fantastic.

To issue a command; to tell.

"He bade me come in."

To invite; to summon.

"She was bidden to the wedding."

To utter a greeting or salutation.

To shell (a walnut).