lacklustreEnglishOxford Dictionary of Englishlacklustre /ˈlakˌlʌstə / (US English lackluster) ▸ adjective 1 lacking in vitality, force, or conviction; uninspired or uninspiring: no excuses were made for the team's lacklustre performance. 2 (of the hair or the eyes) not shining; dull: the conditioner will revitalize lacklustre hair.