not serious

Weak matches

amusing, blithe, capering, clever, comic, comical, droll, dry, fanciful, farcical, flip, flippant, frivolous, funny, humorous, indecorous, ironic, irreverent, jesting, jocose, jocular, joking, joshing, laughable, ludicrous, merry, playful, pleasant, pulling one's leg, punning, putting one on, ridiculous, salty, sarcastic, satirical, smart, sportive, sprightly, waggish, whimsical, wisecracking, witty, wry

Strongest matches

foolish, idiotic, impractical, petty, pointless, senseless

Weak matches

barmy, childish, dizzy, empty-headed, facetious, featherbrained, flighty, flip, flippant, gay, giddy, harebrained, idle, ill-considered, juvenile, light, light-minded, minor, niggling, nonserious, paltry, peripheral, playful, puerile, scatterbrained, shallow, sportive, superficial, tongue-in-cheek, unimportant, unprofound, volatile, whimsical

Strongest matches

empty, unproductive, useless

Strong matches

hollow, rambling

Weak matches

abortive, bootless, frivolous, fruitless, futile, groundless, insignificant, irrelevant, nugatory, of no avail, otiose, pointless, superficial, trivial, unavailing, unhelpful, unnecessary, unsuccessful, vain

Strongest matches

amusing, comic, flippant, humorous, ironic, irreverent, jocular, joking, playful, sarcastic, satirical, whimsical

Strong match

jokingly

Weak matches

blithe, clever, comical, dry, facetious, farcical, flip, funny, in fun, in jest, ironical, jesting, joshing, kiddingly, laughable, pulling one's leg, putting one on, smart, wisecracking, witty

Weak matches

all right, allowable, defensible, excusable, explainable, forgivable, justifiable, minor, not too bad, okay, permissible, slight, tolerable, trivial, understandable