Teflon

noun

• a tough synthetic resin made by polymerizing tetrafluoroethylene, chiefly used to coat non-stick cooking utensils and to make seals and bearings. Also called polytetrafluoroethylene.
• [as modifier] denoting someone whose reputation remains undamaged in spite of scandal or misjudgement:acquittal earned him the nickname ‘the Teflon Don’