Skin, decorticate, peel, pare, flay can mean to divest something of its skin or thin outer covering.
Skin is the most general of these terms, being applicable to any animal as well as to any plant or plant part that is covered by or as if by a skin.
Decorticate is applicable when an outer layer (as of bark, fiber, or husk) is to be removed by stripping.
Peel and pare are frequently interchanged but distinctively peel may imply that the skin or outer covering can be removed by stripping or by pulling off while pare tends to be used when it requires to be cut off, usually with some of the adjoining substance; thus, freshly boiled potatoes can be easily peeled , but uncooked ones must be either scraped or pared ; one speaks usually of peeling an orange because its rind may be stripped by the hand; one speaks usually of paring an apple since the skin is not easily detached from the flesh; one peels a hard-boiled egg. But pare may also be used of anything that is cut close and so is applicable to many things which do not have a skin or rind.
Flay tends to be applied largely to persons often in threats or in descriptions of torture or of cruel punishment (as scourging).