niggling

verb

1. (form-of, gerund, participle, present)present participle and gerund of niggle

adj

1. Petty

   “My dear Hooker, I am getting very much amused by my tendrils, it is just the sort of niggling work which suits me, and takes up no time and rather rests me whilst writing.”

2. Irritating.

   “Sellafield hasn’t suffered an accident of equivalent scale since the 1957 fire, but the niggling fear that some radioactivity is leaking out of the facility in some fashion has never entirely vanished”

noun

1. A small irritating sensation.

   “Occasionally a paranoia or slight insecurity that is not based on reality will bring nigglings of that bad time.”