1) Devalue 2) Frown 3) Frown or scowl 4) Frown, var 5) Gloomy 6) Look angry or sullen 7) Look sullen 8) Lower 9) Make lower or quieter 10) Scowl 11) Scowl, old style 12) Set lower 13) Sullen look 14) To frown 15) To look sullen Found on https://www.crosswordclues.com/clue/lour