Synonyms for Bad:

adj.

bad (adjective)
displeasing, black, baneful, irremediable, unsound, detrimental, faulty, arrant, defective, ill-suited, inferior, inadvisable, wretched, unpleasant, inadequate, invalid, unsatisfactory, poor, wrong, unfavorable, vile.
damaged (adjective)
spoiled.
dangerous (adjective)
risky.
decayed (adjective)
rotten, putrid, spoiled, rancid.
disagreeable (adjective)
objectionable.
distressing (adjective)
distressed, adverse, unpleasant, displeasing, unfavorable, disagreeable, unfortunate, unhappy.
evil (adjective)
damnable, repulsive, nefarious, loathsome, offensive, heinous, hideous, revolting, terrible, foul, baneful, reprehensible, unpropitious, repellent, sinful, evil, detrimental, wicked, sinister, repugnant, calamitous, disgraceful, black, abominable, atrocious, monstrous, destructive.
harmful (adjective)
unhealthy, detrimental, dangerous.
hopeless (adjective)
irremediable, hopeless, helpless.
mischievous (adjective)
ill-behaved, naughty, disobedient.
offensive (adjective)
frightful.
severe (adjective)
distressing, acute, intense, painful, terrible, dangerous, critical, grave, serious.
sick (adjective)
ill, diseased, ailing.
sorry (adjective)
dejected, contrite.
unjust (adjective)
unfair.
wicked (adjective)
debased, depraved, debauched, evildoing, iniquitous, sinister, blameworthy, felonious, lawbreaking, immoral, villainous, reprehensible, improper, corrupt, sadistic, criminal, damnable, perverse, obnoxious, Misdoing, sinful, shocking, indecent, wicked, degenerate, scandalous, black, base, wrongdoing.
wrong (adjective)
faulty, erroneous, flawed, incorrect, untrue, mistaken, improper, aberrant, wrong, illegal, inaccurate, fallacious, false.

adv.

all (adverb)
badly.

n.

inhuman, unkind, uncharitable, pitiless, hateful. diseased, ailing, sick, dire. adverse, burning, achy, agonizing, chapped, agonising, unfortunate, disagreeable, angry, chronic, crippling. disobedient, tasteless, insipid, inedible, bland. excellent, fashionable, preteen, sharp, stylish, prepubescent, adolescent, small, pubescent, effective. difficult, fraught, contentious, dying, invidious, disruptive, in serious trouble, in critical condition, embarrassing, troublesome, in trouble at trouble. control, bleak, unappealing, ill-behaved, unattractive, objectionable. pain, yucky, unsympathetic, uncongenial, debilitating. degrading, discreditable, libellous, scurrilous, unpropitious, inauspicious, compromising, slanderous, luck, defamatory. help. attribute (noun)
badness.
sorry (noun)
distressed, dejected, contrite.
spoiled (noun)
rancid, putrid, decayed.
unfair (noun)
one-sided, partial, unfair, unjustified, wrongful, unequal, arbitrary, unreasonable, unjust, biased.

Other synonyms:

chapped, scurrilous, compromising, dire, degrading, unpropitious, dangerous, contentious, insipid, rancid, peccant, angry, fraught, agonizing, embarrassing, agonising, objectionable, slanderous, discreditable, disruptive, yucky, prepubescent, achy, ill-behaved, unattractive, chronic, pubescent, debilitating, invidious, bland, difficult, crippling, libellous, defamatory, troublesome, gross out. awesome, burning, preteen, small, uncongenial, inauspicious, acute, tasteless, putrid, adolescent. reprobate, bleak, unsympathetic, disagreeable. sharp. gross. corrupt
vicious.
unpalatable
inedible.
Other relevant words:
naughty, objectionable, peccant, lousy, putrid, reprobate, awful, ailing, unhealthy, dangerous, spoiled, untoward, rotten, badly, sick, vicious, ill.

Usage examples for bad

  1. You don't feel too bad to come down, do you?" – The Turmoil A Novel by Booth Tarkington
  2. This is bad enough. – The Anti-Slavery Examiner, Omnibus by American Anti-Slavery Society
  3. And this house isn't so bad either. – The Matador of the Five Towns and Other Stories by Arnold Bennett