To worry someone slightly, usually for a long time. (Cambridge Dictionary)
If something niggles you, it causes you to worry slightly over a long period of time. (Collins Dictionary)
If someone niggles you, they annoy you by continually criticising you for what you think are small or unimportant things. (Collins Dictionary)
Cause slight but persistent annoyance, discomfort, or anxiety. (Oxford Dictionaries)
Criticise or annoy (someone) in a petty way. (Oxford Dictionaries)
To spend too much effort on minor details. (Merriam – Webster)
Watson picks up niggle on day one.
Australia all-rounder Shane Watson picked up a lower leg injury on day one of the first Ashes Test at Trent Bridge. However, his long history of breaking down means any niggle must be treated with concern.
The little niggles you mustn’t just dismiss as signs of ageing: From fatigue to needing the loo more often, the symptoms it’s dangerous to ignore.