Because the question has the tag, here's the etymology.
Knife Anatomy, Parts, Names, Components, Definitions, and Terms says:
The old word, jimp that came from North England and Scotland, means neat, handsome, and slender in form. The knife industry designated regular, machined cuts or cross-hatched patterns on the back of the spine of the knife to improve traction of the fingertips jimping. They still call those regular spaced machine-made cuts jimping, but the in the custom and handmade knife world it has evolved into artistic filework. Jimping may be machine-cut by automated slitters, mills, or blades, but filework must be hand-cut. In my world, calling filework jimping is an insult.
The OED has the noun jimp as an obsolete Scottish meaning, from 1513:
1. A minute or subtle point; a trifling distinction; a quirk, subtlety; a tittle.
And from 1572:
2. A trick, prank.
They say it may be related to the Scottish and northern dialect adjective jimp, variously meaning slender, slim, delicate, graceful, neat or scanty; barely full; bare (measure).
Known in Scots since c1500; origin obscure. It has been compared with gim adj., ‘smart, spruce’, of the same age, and with jump adj., exact, precise, which appears later; but in neither case is the sense congruous.
It's also used as jimp-waisted, such as this from 1826:
That bonnie dark-haired..jimp-waisted lassie.