Oilskin n. : Cloth made waterproof by oil.

Example:
How do you get the "stiffness" out of Oilskin?

Taxonomy
oilskin jackets, jacket, trousers, garments, oilskins, free encyclopedia, sailor, bad weather, walking, harness, shoulder straps, rain, hood, pockets, fabrics, waterproofs, high-visibility, wave.

Defination from the web:
Oilskin trousers are very high-cut for a large overlap with the jacket and prevent water entering through the join. ... The cuffs of better oilskin jackets include an inner seal, something like that on a scuba diver's drysuit, to stop water getting in if a wave is forced up the sleeve. ...