Synonyms for Simplicity (same or very similar meaning)
WordNet sense 1 (a lack of penetration or subtlety):
simplenessWordNet sense 2 (absence of affectation or pretense):
simmplenessWordNet sense 3 (freedom from difficulty or hardship or effort):
ease, easinessWordNet sense 4 (lack of ornamentation):
chasteness, restraintFrom the ODE community, based on WordNetadd/edit