lackluster

Short definition from Wiktionary

Adjective

1. 1
   Lacking brilliance or intelligence.
2. 2
   Having no shine or lustre; dull.
3. 3
   Not exceptional; not worthy of special merit, attention, or interest; having no vitality.

Noun

1. 1
   Lack of brightness or points of interest.
2. 2
   A person or thing of no particular brilliance or intelligence.