Arthur, William (1857) An Etymological Dictionary of Family and Christian Names. New York: Sheldon, Blakeman. Public Domain.
KNAPP
As described in historical dictionaries
An Etymological Dictionary of Family and Christian Names (1857)
(origin: Ger.) Knappe, a lad, boy, servant, workman; a squire, whence Knave and Knapsack.
Patronymica Britannica (1860)
KNAPP. 1. Cwfflp. A-Sax. A top or knop. Bosworth. A hillock or hna}) of a hill. Cotgrave. In Sussex, the brow of a hill is called a nab.
Lower, Mark A (1860) Patronymica Britannica: a dictionary of the family names of the United Kingdom. London: J.R. Smith. Public Domain.
Surname type: Location or geographical feature
Origin: English
Region of origin: British Isles
Country of origin: England
Religion of origin: Christian
Language of origin: English