1rare The action of stripping a person of his or her wealth or assets, especially by dishonest or unscrupulous means. Compare "fleece".
2literal The action or process of removing feathers, especially from the carcass of a poultry bird in preparation for cooking, typically by mechanical means. Also: an instance of this. Frequently attributive, as "defeathering machine", "defeathering tank", etc.
3The shedding of feathers by a bird; specifically loss of feathers on the brood patch on the belly during the breeding season.
Late 19th century; earliest use found in The Graphic: an illustrated weekly newspaper. From defeather + -ing.