The term 'less bright' can be described by the crossword solutions 'dumber' (6 letters), 'paler' (5 letters), 'duller' (6 letters), and 'darker' (6 letters). Dumber is a synonym for less intelligent, paler is a synonym for less colorful, duller is a synonym for less vivid, and darker is a synonym for less luminous. Therefore, the term 'less bright' can be used to describe something that is less intelligent, less colorful, less vivid, or less luminous.