Gwyneth \gw(y)-ne-th\ as a girl's name is of Welsh origin, and the meaning of Gwyneth is "happiness". From "gwynaeth". Of uncertain meaning and also possibly from the Welsh district name Gwynedd, probably from "gwen" meaning "white, fair". Its use in the English-speaking world seems to have been due to the popular novelist Annie Harriet Hughes (19th century) whose pen name was Gwyneth Vaughan. Actress Gwyneth Paltrow.
Gwyneth has 23 variant forms: Cheryth, Gweneth, Gwenetta, Gwenette, Gwenisha, Gwenita, Gwenith, Gwenness, Gwenneth, Gwennetta, Gwenyth, Gwineth, Gwinneth, Gwinyth, Gwynedd, Gwynith, Gwynna, Gwynne, Gwynneth, Winnie, Winny, Wynne and Wynnie.