Oonagh \o(o)-na-gh\ as a girl's name is a variant of Agnes (Greek) and Oona (Scottish, Irish, Gaelic), and the meaning of Oonagh is "pure, holy". See also Una.

The baby name Oonagh sounds like Ang, Angy, Ange, Annaka, Anaka, Anaca, Iniga, Inga, Innga and Inge. Other similar baby names are Oonah and Rionagh.