suprotnost

1. opposite
   On je potpuna suprotnost svom bratu. — He is the complete opposite of his brother.
   Suprotnosti se privlače. — Opposites attract.
2. (u suprotnosti sa) contradiction; contrast
   Ta odluka je u suprotnosti sa zakonom. — That decision is contrary to the law.
   Njegove reči su u suprotnosti s njegovim postupcima. — His words contradict his actions.

"Biti u suprotnosti sa + instr." means "to be contrary to something".