Delwyn

This name is unisex - though the majority of Delwyns in Wales are women.

I'm afraid anyone who says Delwyn is a female name is completely wrong - Wyn at the end signifies the male. The female equivalent is Delyth.

Masculine. My great-grandfather's name and a family name.

I think this should be a masculine name because it ends in the masculine ending "wyn" as opposed to the feminine ending which would be "wen." But I could be wrong. [noted -ed]