Frivolous

a.	1.
	1.	Of little weight or importance; not worth notice; slight; as, a frivolous argument.
	2.	Given to trifling; marked with unbecoming levity; silly; interested especially in trifling matters. His personal tastes were low and frivolous. - Macaulay.

Adj.

1.

frivolous - not serious in content or attitude or behavior; "a frivolous novel"; "a frivolous remark"; "a frivolous young woman" Antonyms: serious - concerned with work or important matters rather than play or trivialities; "a serious student of history"; "a serious attempt to learn to ski"; "gave me a serious look"; "a serious young man"; "are you serious or joking?"; "Don't be so serious!"

aimless, airy, amorphous, asinine, birdbrained, birdwitted, brainless, buxom, capricious, casual, catchpenny, childish, desultory, disarticulated, discontinuous, disjunct, disordered, dispersed, disproportionate, dizzy, empty, empty-headed, erratic, fatuous, featherbrained, featherheaded, fitful, flighty, flimsy, flip, flippant, fluffy, fluttery, foolish, formless, fribble, fribbling, frothy, futile, gaga, giddy, giddy-brained, giddy-headed, giddy-pated, giddy-witted, gleeful, gratuitous, haphazard, harebrain, harebrained, hilarious, hit-or-miss, idle, immethodical, inane, inchoate, incoherent, inconsequential, indiscriminate, insignificant, irregular, irresponsible, jocular, jocund, jolly, jovial, joyful, joyous, laughter-loving, light, meaningless, merry, minor, mirth-loving, mirthful, misshapen, niggling, nonsymmetrical, nonsystematic, nonuniform, nugacious, nugatory, orderless, otiose, paltry, peripheral, petty, planless, playful, promiscuous, puerile, random, rattlebrained, rattleheaded, rattlepated, rejoicing, risible, scatterbrained, scramblebrained, senseless, shallow, shallow-headed, shallow-minded, shallow-pated, shallow-witted, shapeless, shatterbrained, silly, slender, slight, small-time, spasmodic, sporadic, straggling, straggly, superficial, systemless, thoughtless, trifling, trite, trivial, two-bit, twopenny, unarranged, unclassified, undirected, ungraded, unimportant, unjoined, unmethodical, unordered, unorganized, unprofound, unsorted, unsymmetrical, unsystematic, ununiform, vacuous, vague, vain, vapid, volatile, wandering, windy, witless, worthless