Definition of optimity in US English:

optimity

noun

rare
  • The quality or fact of being the best or very good; excellence.

Origin

Mid 17th century; earliest use found in Thomas Blount (1618–1679), antiquary and lexicographer. From post-classical Latin optimitas the quality or fact of being the best from classical Latin optimus best + -tās.

Pronunciation

optimity

/ɒpˈtɪmɪti/