unfunny
From Longman Dictionary of Contemporary Englishunfunnyun‧fun‧ny /ʌnˈfʌni/ adjective informal an unfunny joke or action is not amusing, although it is intended to be – used to show disapprovalExamples from the Corpusunfunny• I have told him that he is being very unfunny.• As you may have noticed, almost anyone in Hollywood can make an unfunny comedy.• He called Marro seven more times over the weekend to remind him just how unfunny it was.