frabjous
Fabulous, joyous; great, wonderful.
“[…] O frabjous day! Callooh! Callay!” He chortled in his joy.
Where it comes from
Originally a nonce word in Lewis Carroll's poem “Jabberwocky” (see the quotation); probably a blend of fair + fabulous + joyous.
Adapted from the Wiktionary entry frabjous (CC BY-SA 4.0).