Etymology
English surname, from the obsolete English given name Waltheof, from Old English weald (“power”) + þēof (“thief”), as in "one who snatched victory from battle." Comparable to, or ultimately Anglicized from, the Old Norse equivalent Valthiófr, from vald + *ᚦᛖᚢᛒᚨᛉ (*þeubaʀ). Compare Walthall, Waldie.
Definitions & examples from Wiktionary (CC BY-SA 3.0).