Grinchgender

Someone who identifies as a grinch, they may express this by dressing up as the grinch, hating christmas and actively tries to ruin fun for others.

Chelsea: I'm cooking up a nice big roast turkey for christmas.

Kayleigh: yuck! All that effort for some dry chewy flavourless meat... Christmas is just some commercial crap anyway.

Chelsea: oh yeah, I forgot you were grinchgender...