bad - definition of bad by The Free Dictionary
bad 1 (băd) adj. worse (wûrs), worst (wûrst) 1. Not achieving an adequate standard; poor: a bad concert. 2. Immoral or evil. 3. Vulgar or obscene: bad language. 4. Disobedient or naughty: bad children. 5. Disagreeable, unpleasant, or disturbing: a bad pie...