This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

adj. Alternative spelling of lackluster.

adj. lacking brilliance or vitality

adj. lacking luster or shine

"His opponents within Labour say what they call his lacklustre leadership will ensure electoral defeat."

dull   

brass-colored    buildable    purplish-grey    scantier    cactus-like    bluish-grey    germinative    too-a    duskier    dicotyledonous