IPA: /dʒəˈkɒsɪti/
KK: /dʒoʊˈkɑsɪti/
The quality or state of being cheerful and full of fun; humor or playfulness.
Her jocosity made the party lively and enjoyable for everyone.
Jocosity → It is formed from "jocus" (from Latin, meaning joke or jest) and the suffix "-ity" (meaning the state or quality of). The word "jocosity" refers to the quality of being humorous or playful, akin to the nature of a joke.
Think of 'jocus' which means joke, and remember that 'jocosity' describes the quality of being playful or humorous.
No commonly confused words.