Meaning A boy's name of Irish origin, it means "kind one." Origin of Uilliam Celtic , Irish +-100%Zoom level changed to 1 Popular Middle Names Ray Pronunciation 🔊 Listen Uilliam Similar Names Benen Aadvay Abdul Hafee Abdur Raoof Finn Desmond Cian Piran Aalif Gilmore Year by Year Popularity of Uilliam