vapid

Offering nothing that is stimulating or challenging.

• In Koons' best-known works—a life-sized poly-chromed wood replica of Michael Jackson and his pet chimp Bubbles; vapid fin de siècle readymades such as a trio of basketballs floating in a fishtank […]

Lifeless, dull, or banal.

• Then there was a little more trite conversation between Mr. Arabin and Mr. Harding; trite, and hard, and vapid, and senseless.

Tasteless, bland, or insipid.