The suspension, which is Deeney's second of the season after already accepting a retrospective charge for violent conduct in late October, will see him miss the entire festive period as the Hornets contend with a packed schedule between now and early January.
⚽ | #watfordfc has learned from The Football Association that its appeal lodged against Troy Deeney’s red card on Saturday (Dec 16 v Huddersfield Town) has been unsuccessful.— Watford FC (@WatfordFC) December 19, 2017
Troy will therefore serve a four-match ban covering the games Dec 23, Dec 26, Dec 30 & Jan 2. pic.twitter.com/7ZsQgqEsUT
The 29-year-old striker was dismissed against Huddersfield after a reckless challenge on Terriers forward Colin Quaner was deemed by referee Michael Oliver to be serious foul play.
The first game Deeney will miss comes away against Brighton on Saturday in the final game before Christmas. He will then be out of the Boxing Day clash with Leicester at Vicarage Road, followed by the home game with Swansea on 30th December and the first game of 2018 when the team travels to the Etihad Stadium to face league leaders Manchester City on 2nd January.
Having been in and out of new manager Marco Silva's plans earlier in the season, Deeney had actually started four Premier League games in a row prior to Saturday's red card.
He has scored twice in the league so far in 2017/18, with Watford's top scorers midfield dynamo Abdoulaye Doucoure on six and Brazilian winger Richarlison on five.