Definition of "Bad" :

noun: that which is below standard or expectations as of ethics or decency

"Take the bad with the good."

adjective: feeling physical discomfort or pain (tough' is occasionally used colloquially for bad')

"My throat feels bad."

adjective: (of foodstuffs) not in an edible or usable condition

"Bad meat."

adjective: not working properly

"A bad telephone connection."

adjective: reproduced fraudulently

"Like a bad penny...."

adjective: having undesirable or negative qualities

"A bad report card."

adjective: characterized by wickedness or immorality

"Led a very bad life."

adjective: feeling or expressing regret or sorrow or a sense of loss over something done or undone

"He felt bad about breaking the vase."

adjective: capable of harming

"Bad air."

adjective: physically unsound or diseased

"Has a bad back."

adjective: very intense

"A bad headache."

adjective: not financially safe or secure

"A bad investment."

adjective: nonstandard

"So-called bad grammar."

adjective: below average in quality or performance

"A bad chess player."

adjective: not capable of being collected

"A bad (or uncollectible) debt."

adverb: very much; strongly

"I wanted it badly enough to work hard for it."

adverb: with great intensity (bad' is a nonstandard variant for badly')

"The injury hurt badly."