A bumsook is a person who wants to be the favourite to everyone! Also known as a teachers pet.
'how much of a bumsook Kieran is!

'omg they had kinky bumsook sex'
by bumsook2k16 December 6, 2016
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bumsook is a term used for when someone sucks up to someone else. Constantly agreeing with them, random unnecessary compliments, following all signs of a bumsook
Ugh Craig is such a bumsook to Finlay, he’s obsessed !
by Big Mergan November 7, 2019
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