lackluster

Lacking brilliance or intelligence.

Having no shine or lustre; dull.

A faded, and an ancient dragon he was; and many a wintry storm of rain, snow, sleet, and hail, had changed his colour from a gaudy blue to a faint lack-lustre shade of gray.

He sat looking at her with lack-lustre eyes. The light suddenly came back into them.

Not exceptional; not worthy of special merit, attention, or interest; having no vitality.

The actor gave a lackluster performance in his latest film.

An allegedly true story emerges as a lackluster riff on American Hustle and The Wolf of Wall Street with a scrappy turn from an overly disguised lead star[.]

Lack of brightness or points of interest.

A person or thing of no particular brilliance or intelligence.