Sinead \s(i)-nead\ as a girl's name is pronounced sha-NADE. It is of Irish and Hebrew origin, and the meaning of Sinead is "God is gracious". Variant of Jane or Janet, which are feminine forms of John. Sinead was made familiar to Americans by singer Sinead O'Connor. Actress Sinead Cusack.
For more information, see also the related name Shanae.