WordWeb Online

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, bicker, squabble, brabble

Derived forms: niggling, niggles, niggled

See also: niggler

Type of: argue, contend, debate, fence, sweat, worry

Encyclopedia: Niggle