Flapkut etymology in Dutch

Dutch word flapkut comes from Dutch kut

Dictionary entry	Language	Definition
kut	Dutch (nl)	(Brabant, invective) showing deliberately annoying behavior to someone or to mock someone or to disadvantage someone. (vulgar, slang, Netherlands) crap, not entertaining (chiefly Brabantian, derogatory) a strongly disliked person; cunt, bastard. (vulgar, slang) vulva, especially the vagina; cunt, pussy (vulgar, slang, Netherlands) fuck!.
flapkut	Dutch (nl)

Flapkut etymology