IPA: /ˈlʌstərləs/
KK: /ˈlʌstərləs/
Not shiny or bright; lacking in brightness or vitality.
The lusterless paint made the room feel dull and uninviting.
Comparative: lusterless
Superlative: most lusterless
Lusterless is formed from "luster" (from Old French *lustre*, meaning brightness or sheen) and "-less" (meaning without). The word "lusterless" means lacking brightness or sheen.
Think of 'luster' as brightness or shine, and remember that 'lusterless' means without that shine.