About the McGuiness surname
The surname McGuiness is associated with a patronymic formation. The Mac-/Mc- formation is traditionally patronymic and means “son of” in Gaelic languages. A patronymic formation of this kind shows how an older personal name could develop into a family name. The prefix in McGuiness belongs to a family of Gaelic forms traditionally used in patronymic surnames and is generally associated with descent.
Pronunciation:
Èm-sé-gaj-neus/ɛmseɡajnœs/