1. [adj]  lacking spontaneity or originality or individuality; "stereotyped phrases of condolence"; "even his profanity was unimaginative"
2. [adj]  deficient in originality or creativity; lacking powers of invention:i"a sterile ideology lacking in originality"; "unimaginative development of a musical theme"; "uninspired writing"
3. [adj]  dealing only with concrete facts

UNIMAGINATIVE is a 13 letter word that starts with U.