Kenneth G. Wilson (1923–). The Columbia Guide to Standard American English. 1993.
bad (adv., adj.), badly (adv.), bad(ly) off (adv.)
Bad as adjective is Standard in both attributive and predicate adjective use: This puts us in a bad light. The light is bad in here. Bad as adverb works Conversationally and Informally almost exactly as does the older badly: We all did bad [badly] on the exam. My arm was hurting bad [badly] after the game. But bad as adverb in other levels is Common English at best and is clearly not acceptable in Edited English. As an intensifier, only badly is Standard: She was badly injured in the accident. Bad and badly with linking verbs, such as look, seem, appear, and the like are discussed in the entry for FEEL BAD. See also FLAT ADVERBS.
