1. Dull-witted, stupid, and confused: "Someone who is obviously addle-brained is Democratic Congressman Anthony Weiner, of New York, who said he had been engaged in several inappropriate electronic relationships with six women over three years, and that he publicly lied about a photo of himself sent over Twitter to a college student in Seattle over a week ago."
2. Crazy, weak, mentally deficient in some way: "Is it possible that Dominique Strauss-Kahn, the former managing director of the International Monetary Fund, was addle-brained when the hotel-cleaning woman went into his room while he was still naked and he forced her to have oral sex with him?"