A French expression derived from the saying young people use "il a des dettes et des sous" which means "he has debts and
cash". Mixing debts and
cash, came detsou.
Without the money aspect, it is now used to describe someone who's
legendary for its ability to play games and mindfuck its entourage, strangers and even animals if he wanted to.
"Joue pas au Loup-Garou avec ce
type, c'est un putain de Detsou."
"Don't
play Mafia with that
guy, that's a freacking Detsou."