Noun.

Around Halloween season and on all soul's eve and it's related parties and drunken get-togethers, college age and night club scene women will wear costumes that are thinly veiled outfits to a theme but are just slutty in nature and to display the assets. Halloween simply serves as a convenient excuse for these girls to dress and act as slutty as possible without negative repercussion and backlash.

Slut Costume.
That Halloween store will sell out of slutstumes like they do every year before Halloween.

Let's count how many blondes will wear their slutstumes compared to brunettes and redheads.
by Jiggly-Licious October 4, 2019
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Feminine attire so revealing and ridiculous that it can only be worn to Halloween parties
Confusingly, Jeneva looked kinda hot in her Hello Kitty slutstume.
by Kegley October 31, 2011
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