I don't think the word "niggling" is very good.

here is an article i read excerpt by a mister derbyshire:

"It was in conversation with friends (all nonblack) that I saw some of the other side of the issue. One friend, who has serious credentials as a conservative thinker, said this: "John, you are a gentleman, and I know you would not knowingly give unnecessary offense. I am sure, therefore, that you would in fact avoid the word 'niggardly' in a group that included not-very-well-educated black fellow citizens." I had to admit that he was right: I would. Later that evening, watching TV, I caught a very good biographical program about the jazz singer Ella Fitzgerald. Now I am a huge fan of Ella, who was of course black. At the same time, the program confirmed a thing I had suspected from similar material: she had little education, and in fact was probably not very bright. So: Here is a black person who I admire tremendously, and in whose presence (which I never was) I would be awestruck; yet for whose intellect (other than musical) I have no very high regard. Would I have used "niggardly" in conversation with Ella? No, of course I wouldn't."