0 worrying someone slightly or causing them slight pain, usually for a long time:
1 criticizing someone about small details or giving too much attention to details:
2 (of thoughts, worries, or details) unimportant but demanding one’s attention in an annoying way:
She doesn't want to solve all the niggling little problems that users come up with.
I have this niggling little doubt about whether I can pass this exam.
His job is to deal with the niggling issues each decision generates.
It is a very interesting company, whatever niggling complaints I might have had.
Her boss undermined her confidence by making constant niggling demands.
