felicity vs happiness

felicity and happiness both are nouns.

Word	Noun	Adjective	Verb	Adverb
felicity	Yes	No	No	No
happiness	Yes	No	No	No

As nouns, felicity and happiness are synonyms defined as:

felicity and happiness: state of well-being characterized by emotions ranging from contentment to intense joy

felicity (noun)	happiness (noun)
pleasing and appropriate manner or style (especially manner or style of expression)	emotions experienced when in a state of well-being
state of well-being characterized by emotions ranging from contentment to intense joy	state of well-being characterized by emotions ranging from contentment to intense joy