Lackluster:
adjective
1. lacking brilliance or radiance; dull: lackluster eyes.
2. lacking liveliness, vitality, spirit, or enthusiasm: a lackluster performance.
Dull:
adjective
1. not sharp; blunt: a dull knife.
2. causing boredom; tedious; uninteresting: a dull sermon.
3. not lively or spirited; listless.