1. [informal] Small and of little importance
   "a dispute over niggling details";
   - fiddling [informal], footling [informal], lilliputian [informal], little [informal], piddling [informal], piffling [informal], petty [informal], picayune [N. Amer, informal], trivial [informal], niggly [informal], piddly [informal]
    
2. Causing slight but persistent discomfort or anxiety
   "a niggling pain in his knee"

1. Worry unnecessarily or excessively
   "don't niggle too much over the grandchildren—they are quite big now";
   - fuss, fret
    
2. Argue over petty things
   "Let's not niggle over pennies";
   - quibble, pettifog [archaic], bicker, squabble, brabble [archaic]

See also: unimportant

Type of: argue, contend, debate, fence, sweat [N. Amer, informal], worry

Encyclopedia: Niggling