adj.無光澤的；暗淡的；無生氣的
n.無光澤；暗淡 無生氣；平凡
The audience was disappointed and rather angry when the famous musician performed in a lackluster manner after arriving late for the concert. 這位著名的音樂家演出遲到后平平淡淡地表演了一番，觀眾很失望，非常生氣。
