As is suggested in the entry ILLEGAL, illicit means "unlawful," "not sanctioned or authorized," "improper": "Millie was accused of being an illicit trader in cigarettes." "You are in illicit territory because this area is off bounds to all personnel." Licit means the direct opposite of illicit. Elicit means "to bring out," "to draw forth": "The judge tried to elicit the truth from this defendant." "The politician tried hard to elicit a favorable response from the assembled crowd."
Dictionary of problem words and expressions. Harry Shaw. 1975.