Wielding a FOIL is a fencing technique used in the sport of fencing. It involves using a thin, blunted SWORD-like weapon to attack and defend against an opponent. The term 'wield a FOIL' is derived from the French word for 'SWORD, ' which is 'FOIL.' Fencing is a sport that has been around since the 16th century and is still popular today. The FOIL is one of three weapons used in fencing, along with the epee and sabre.