A ghillie suit is a type of camouflage clothing designed to resemble the background environment such as foliage, snow or sand. Typically, it is a net or cloth garment covered in loose strips of burlap (hessian), cloth, or twine, sometimes made to look like leaves and twigs, and optionally augmented with scraps of foliage from the area.
Military personnel, police, hunters, and nature photographers may wear a ghillie suit to blend into their surroundings and conceal themselves from enemies or targets. The suit gives the wearer's outline a three-dimensional breakup, rather than a linear one. When manufactured correctly, the suit will move in the wind in the same way as surrounding foliage. Some ghillie suits are made with light and breathable material that allows a person to wear a shirt underneath.
A well-made ghillie suit is extremely effective in camouflaging its wearer. A ghillie-suited soldier sitting perfectly still with local flora attached to their webbing is nearly impossible to detect visually, even at close range. However the suit does nothing to prevent thermal detection using technologies such as FLIR. In fact, the warmth of the heavy suit can make a wearer stand out more than a standard soldier when viewed using these methods.
The word ghillie is a reference to Ghillie Dhu, a fairy clothed in leaves and moss in Scottish mythology.
The Lovat Scouts, a Scottish Highland regiment formed by Simon Fraser, 14th Lord Lovat during the Second Boer War, is the first known military unit to use ghillie suits and in 1916 went on to become the British Army's first sniper unit. The Lovat Scouts were initially recruited from the ranks of Scottish Highland estate workers, especially professional stalkers and gamekeepers, with some of them coming from Gairloch, where the tale of Ghillie Dhu originates.
Similar sniper outfits in the Australian Army are nicknamed "yowie suit", named for their resemblance to the Yowie, a mythical hominid similar to the Yeti and Bigfoot which is said to live in the Australian wilderness.