1. The quality of being nice
   "Her niceness made her popular among her classmates"
    
2. A courteous manner that respects accepted social usage
   "His niceness charmed everyone at the party";
   - politeness, politesse
    
3. The quality of being difficult to detect or analyse
   "you had to admire the niceness of the distinctions he drew";
   - subtlety

See also: impolite, nice, polite

Type of: courtesy, difficultness, difficulty, good manners, pleasantness, pleasurableness, sweetness

Antonym: impoliteness, nastiness

Encyclopedia: Niceness