‘Niggle’ is a word that you don’t seem to hear as often as you once did, but I still like to use it. I like the way it sounds – particularly when you’re annoyed because of the way you can emphasis the ‘n’ and ‘g’s.
It’s a reasonably old word, with an even older origin (or so they think) coming from an Old Norse word: ‘nigla’.
And no it doesn’t have any relation to that somewhat similar sounding word that comes from ‘negro’ which is Spanish for the colour black.