Felicity means great happiness or source of great happiness.
Felicity is a noun.
Synonyms: bliss, elation, joyfulness, happiness, delight, exultation.
Antonyms: sadness, sorrow, misery, unhappiness, woe.
The felicities of life in the state are endless.
The felicitous expressions of the guest warmed the entire members.
How did you learn to speak with such felicity?