Boy name origins & meanings Spanish : Resolute, protectorTeutonic : Valiant protector Boy name variations Guillermo Guilherme Gillermo Gughilmo Gwillyn Gwilym William Wil Will Willem Wilhelm Wilmos Wilmot Wilson Williams Williamson Wills Willie Willy Wiley Wyley Wilkie Willkie Wilkes Wylkes Willis Wilton Wilmer Wilmar Winton Willard Wilford Vilhelm Vilem Viliam Vasili Vasily Uilleam Uilliam Family name origins & meanings French : from the personal name Guillaume, French form of William.