"Mushroom haters" refers to people who strongly dislike or have a strong aversion towards mushrooms.
Full definition
Until a few years ago I was
a mushroom hater.
These will convert even
those mushroom haters out there.
Even
mushroom haters will like it (I used to be a mushroom hater myself!)
We have
some mushroom haters in the family.
I left the mushrooms off because he's
a mushroom hater but I might use them next time and just tell him to pick around!
We have served this burger to meat - eating guys and
mushroom haters and it has won the love from them all.
You could leave these out if you're
a mushroom hater, but please don't, they make this Garlic Parmesan Gnocchi extra delicious!