FACETIOUSLY
facetiously, jokingly, tongue-in-cheek
(adverb) not seriously; “I meant it facetiously”
Source: WordNet® 3.1
Etymology
Adverb
facetiously (comparative more facetiously, superlative most facetiously)
In a facetious or flippant manner; in a manner that treats serious issues with deliberately inappropriate humor
(dated) In a pleasantly humorous or playful fashion.
Synonyms
• (with inappropriate humor): flippantly
• (in a pleasantly humorous fashion): humorously, jocularly, playfully
Source: Wiktionary
FACETIOUS
Fa*ce"tious, a. Etym: [Cf. F. facétieux. See Facetiæ.]
1. Given to wit and good humor; merry; sportive; jocular; as, a
facetious companion.
2. Characterized by wit and pleasantry; exciting laughter; as, a
facetious story or reply.
– Fa*ce"tious*ly, adv.
– Fa*ce"tious*ness, n.
Source: Webster’s Unabridged Dictionary 1913 Edition