simpleness in WordNet English dictionary

1. lack of ornamentation
   "the room was simply decorated with great restraint"
   chasteness  restraint  simplicity  simpleness 
   
2. freedom from difficulty or hardship or effort
   "he rose through the ranks with apparent ease"; "they put it into containers for ease of transportation"; "the very easiness of the deed held her back"
   ease  easiness  simplicity  simpleness 
   
3. a lack of penetration or subtlety
   "they took advantage of her simplicity"
   simplicity  simpleness  simple mindedness 
   
4. the quality of being simple or uncompounded
   "the simplicity of a crystal"
   simplicity  simpleness