Wikisaurus:bad

In the sense of of inferior quality

• below par,
• broken,
• bum,
• cheap,
• chintzy,
• crappy,
• crummy,
• flimsy,
• inferior,
• lousy,
• low,
• not up to snuff,
• pitiful,
• poor,
• shoddy,
• unacceptable,
• unfit,
• unsatisfactory,
• unsound,
• unsuitable

• good,
• quality,
• solid,
• sound

In the sense of amoral

• evil,
• hellbound,
• iniquitous,
• nasty,
• no-good,
• reprehensible,
• reprobate,
• sinful,
• vicious,
• wicked,
• wrong
• bad seed,
• bad apple,
• bad to the bone

• angelic,
• good,
• just,
• moral,
• righteous

In the sense of incorrect

• errant,
• incorrect

• correct,
• good,
• right

In the sense of rotted

• curdled,
• moldy,
• off,
• putrid,
• rancid,
• rotten,
• sour,
• spoiled

• gone by the wayside,
• past its prime

In the sense of of poor attitude

• abysmal,
• awful,
• crummy,
• dire,
• disagreeable,
• dismal,
• dreadful,
• foul,
• hideous,
• hopeless,
• horrid,
• horrible,
• intolerable,
• loathsome,
• lousy,
• miserable,
• odious,
• rotten,
• terrible