Two Latin phrases commonly used today . persona non grata : someone unwelcome due to ideological differences . Quid pro quo refers to a profession or trade . Sui est refers to something so new or unusual it defies categorization .
Nine Latin phrases commonly used today . Persona non grata : Person unwelcome due to ideological differences . Quid pro quo refers to a deal or trade . Sui generis refers to something so new or bizarre it defies categorization .