RichThesaurus
spoilsport
vs
stick-in-the-mud
spoilsport
adj
Like a spoilsport.
noun
Someone who puts an end to others' fun, especially harmless fun.
stick-in-the-mud
How often have the words
spoilsport
and
stick-in-the-mud
occurred in a corpus of books?
(source:
Google Ngram Viewer
)