¹flat

level, flat, plane, even, smooth mean having a surface without bends, curves, or irregularities. level applies to a horizontal surface that lies on a line parallel with the horizon <the vast prairies are nearly level>. flat applies to a surface devoid of noticeable curvatures, prominences, or depressions <the work surface must be flat>. plane applies to any real or imaginary flat surface in which a straight line between any two points on it lies wholly within that surface <the plane sides of a crystal>. even applies to a surface that is noticeably flat or level or to a line that is observably straight <trim the hedge so it is even>. smooth applies especially to a polished surface free of irregularities <a smooth skating rink>.

insipid, vapid, flat, jejune, banal, inane mean devoid of qualities that make for spirit and character. insipid implies a lack of sufficient taste or savor to please or interest <an insipid romance with platitudes on every page>. vapid suggests a lack of liveliness, force, or spirit <an exciting story given a vapid treatment>. flat applies to things that have lost their sparkle or zest <although well-regarded in its day, the novel now seems flat>. jejune suggests a lack of rewarding or satisfying substance <a jejune and gassy speech>. banal stresses the complete absence of freshness, novelty, or immediacy <a banal tale of unrequited love>. inane implies a lack of any significant or convincing quality <an inane interpretation of the play>.