to criticize, especially constantly or repeatedly, in a peevish or petty way; carp: to niggle about the fine points of interpretation; preferring to niggle rather than take steps to correct a situation.
2.
to spend too much time and effort on inconsequential details: It's difficult to be meticulous and not niggle.
3.
to work ineffectively; trifle: to niggle with an uninteresting task.
Origin: 1610–20; < Scandinavian; compare Norwegian nigla to be penurious (ultimately < Old Norse hnøggr stingy, cognate with Old English hnēaw); compare niggard