/lak"lus'teuhr/ , adj.
1. lacking brilliance or radiance; dull: lackluster eyes.
2. lacking liveliness, vitality, spirit, or enthusiasm: a lackluster performance.
n.
3. a lack of brilliance or vitality.
Also, esp. Brit., lacklustre .
[ 1590-1600; LACK + LUSTER 1 ]