How did the Black Númenóreans self-identify?

Would the Black Númenóreans have called themselves ‘Black Númenóreans’ or did they simply think of themselves as 'Númenóreans'? 'Black' seems to me to be a pejorative given by the men of Gondor for their enemies, but I can't find a source on this.

In either case, how plausible is it that the descendants of Castamir the Usurper would considered themselves to be ethnically the same as the original Númenórean colonisers of Umbar, despite the fact that that line was, as far as we know, broken, and the original Númenóreans of Umbar dispersed?