As described in historical dictionaries

An Etymological Dictionary of Family and Christian Names (1857)

(origin: Nor. Fr. Local) From the town of Agneau in Normandy, whence the family originated. They went from England into Ireland with Strongbow. Agneau, in Nor. Fr. signifies a lamb.

Arthur, William (1857) An Etymological Dictionary of Family and Christian Names. New York: Sheldon, Blakeman. Public Domain.


Patronymica Britannica (1860)

AGNEW. Possibly from the French arjneav, a lamb ; but more likely from Agneaux, a village in the arrondisseraent of St. Lo, in Normandy. Co. Wigton, XIV. cent.

Lower, Mark A (1860) Patronymica Britannica: a dictionary of the family names of the United Kingdom. London: J.R. Smith. Public Domain.


Origin: Celtic

Region of origin: British Isles

Country of origin: Scotland

Religion of origin: Christian

Language of origin: Gaelic

BritishSurnames.uk is a Good Stuff website.