—adv. 1. in a defective, incorrect, or undesirable way: The car runs badly. 2. in an unsatisfactory, inadequate, or unskilled manner: a vague, badly written letter; He paints badly. 3. unfavorably: His neighbors spoke badly of him. The weather turned out badly for the cruise. 4. in a wicked, evil, or morally or legally wrong way.
5. in a disobedient, naughty, or ethically or socially wrong way: He treats his parents badly. 6. very much; to a great extent or degree: a house badly in need of repair; to want something badly. 7. severely; direly: to be injured badly. 8. with great distress, resentment, regret, or emotional display: She took the news of her mother's death badly. 9. badly off. See bad (def. 47).
—adj. 1. in ill health; sick: He felt badly. 2. sorry; regretful: I feel badly about your reaction to my remark. 3. dejected; downcast.