serious

vexatious, meritless, baseless, unnecessary, silly, unmeritorious, specious, trivial, absurd, outrageous, nonsensical, preposterous, ludicrous, outlandish, ridiculous, extravagant, superfluous, childish, unserious, groundless, unwarranted, unfounded, wasteful, disingenuous, unsubstantiated, vexatious litigation, unreasonable, pointless, spurious, wrongheaded, asinine, trite, indecorous, vindictive, irresponsible, fallacious, nugatory, vacuous, tacky, ad hominem, punitive, irrelevant, dismissible, puerile, unoriginal, misguided, inconsequential, laughable, overreaching, extraneous, unmerited, infantile, litigious, faddish, unjustified, dishonest, vulgar, unsupportable, unprofessional, unjustifiable, counterproductive, dilatory, banal, hypocritical, demeaning, illogical, unsubstantial, meretricious, meanspirited, uncalled, victimless, infra dig, unethical, petty, scurrilous, unprovable, untrue, sour grapes, slanderous, stupid, vapid, meaningless, needless, unimportant, fatuous, futile, useless, insincere, insubstantial, inappropriate, fanciful, crass, unobjectionable, superficial, trifling, nitpicking, overindulgent, contumacious, foolish, tiresome, unfair, inessential, harmless, commonplace, prosaic, thoughtless, ignoble, spiteful, deceitful, immoral, unspiritual, contentious, flighty, flippant, innocent, mundane, perverse, selfish

badinage, dilettante, dilettanteish, dilettantish, flighty, flyaway, frivolity, frivolously, frivolousness, game, lightheadedness, lightsomeness, pettiness, sciolistic, silly season, slightness, triviality, vanity fair

airheaded, dizzy, empty-headed, featherbrained, giddy, idle, light, light-headed, light-minded