Crossword clues for the word: LIGHTENUP The word LIGHTENUP has appeared as an answer to at least 9 crossword clues on different crossword puzzles. Crossword clues for LIGHTENUP Showing 1 to 9 of 9 results Clue(s) """Don't act so serious!""" """Don't be so serious!""" """Relax, will ya!""" Become less serious Chill out It's the responsibility of the luminary to relax Relax, to a dietician? Stop being so serious Unwind the flexes with plug in