say it: LA-kluh-stur
lackluster is an adjective meaning "lacking brilliance or vitality". It carries 2 recorded senses.
lacking brilliance or vitality
“a dull lackluster life”
“a lusterless performance”
Definitions, synonyms and semantic relations for lackluster come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.