Synonyms of 'killjoy'
If you say that someone is a spoilsport, you mean that they are behaving in a way that ruins other people's pleasure or enjoyment.
a jealous spoilsport who can't take a joke
Thesaurus for killjoy from the Collins English Thesaurus
If you call someone a killjoy , you are critical of them because they stop other people from enjoying themselves, often by reminding them of something unpleasant .