This interesting surname is of Scottish origin, and is a reduced form of "Macilvernock", itself an Anglicization of the Old Gaelic "Mac GilleMhearnaig". The Gaelic prefix "Mac" denotes "son of", "gille", literally meaning "servant", but used here in the sense of "devotee, follower", and the saint's name "Mearnag", representing a diminutive of "mear", wild, solitary; hence,"son of the follower of (St.) Mearnag".
Gillemernoch, brother of Gilleasald M'Gilleandris in Ayrshire, witnessed a charter by Roger de Scalebroc in favour of Melrose Abbey, circa 1185, in the parish of Borgue, Kirkcudbrightshire, in the reign of Robert 1 (1306 - 1329). These lands were named from the family, and in 1464 were recorded as "Gaitgillmakkilwernock".
The curtailed form of the name first appears on record at the beginning of the 16th Century. One John Warnok was recorded in Glasgow, circa 1530, and a James Warnok was a witness in Ayrshire in 1562. James and Agnes Warnock, residents in the parish of Borgue, were recorded in the "Register of the Privy Coucil of Scotland" in 1684, and on November 22nd 1685, the christening of David, son of James Warnock and Janet Scoty, took place in Barony, Lanarkshire.
The first recorded spelling of the family name is shown to be that of Andree Warnoche, which was dated 1505, in the "Crinimal Trials of Scotland", during the reign of King James 1V of Scotland, 1488 - 1513.