lacklustre

 
Pronunciation: /ˈlaklʌstə/
(US lackluster)

adjective

  • 1lacking 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

Spelling help

The ending of lacklustre is -tre (the spelling lackluster is American).