Not to be a killjoy fact-checker, but this does seem like an important detail to get right.
I dont want to be shown up as a fraid cat and a killjoy, cried Jessie.
Some of you do not like to be reminded of it, and think it a killjoy.
However, I did my utmost to bear a cheerful and contented mien, for killjoy is but a poor friend.
Allan, I don't want to be a killjoy, but you asked for my advice.
I did not wish to be a killjoy and a marplot, or I would have forbidden Fred to touch a foot-ball after he entered college.