THESAURUS
Vapid
airy, arid, asinine, barren, betwixt and between, blah, bland, blank, bloodless, boring, catchpenny, changeable, characterless, cold, colorless, common, commonplace, dead, dilute, diluted, dismal, draggy, drearisome, dreary, driveling, dry, dryasdust, dull, dusty, effete, elephantine, empty, empty-headed, empty-minded, empty-pated, empty-skulled, etiolated, fade, fair, fair to middling, fairish, fatuous, flat, flavorless, flimsy, foolish, fribble, fribbling, frivolous, frothy, futile, gruelly, halfhearted, heavy, ho-hum, hollow, humdrum, idle, inane, indecisive, indifferent, inexcitable, infirm of purpose, infirm of will, innocuous, insipid, irresolute, jejune, lackluster, leaden, lifeless, light, low-spirited, matter-of-fact, mediocre, medium, middling, mild, milk-and-water, milky, moderate, modest, mundane, mushy, namby-pamby, neutral, nugacious, nugatory, of a kind, of a sort, of sorts, ordinary, otiose, pale, pallid, pappy, passable, pedestrian, plain, plodding, poetryless, pointless, poky, ponderous, prosaic, prosing, prosy, pulpy, rattlebrained, rattleheaded, respectable, sapless, savorless, scatterbrained, shallow, silly, slender, slight, slow, so-so, solemn, spiceless, spiritless, stale, sterile, stiff, stodgy, stuffy, superficial, tame, tasteless, tedious, thin, tiresome, tolerable, trifling, trite, trivial, unembellished, unflavored, unidealistic, unimaginative, unimpassioned, uninteresting, unlively, unpalatable, unpoetic, unromantic, unsavory, vacant, vacuous, vain, washy, watered, watered-down, watery, weak, wearisome, wearying, windy, wishy-washy, wooden
ROGET THESAURUS
Vapid
Feebleness
N
feebleness, feeble, bald, tame, meager, jejune, vapid, bland, trashy, lukewarm, cold, frigid, poor, dull, dry, languid, colorless, enervated, proposing, prosy, prosaic, unvaried, monotonous, weak, washy, wishy- washy, sketchy, slight, careless, slovenly, loose, lax (negligent), slipshod, slipslop, inexact, puerile, childish, flatulent, rambling.
Dullness
N
dullness, heaviness, flatness, infestivity &c, stupidity want of originality, dearth of ideas, prose, matter of fact, heavy book, conte a dormir debout, platitude, dull, dull as ditch water, unentertaining, uninteresting, flat, dry as dust, unfunny, unlively, logy, unimaginative, insulse, dry as dust, prosy, prosing, prosaic, matter of fact, commonplace, pedestrian, pointless, weary stale flat and unprofitable, stupid, slow, flat, insipid, vapid, humdrum, monotonous, melancholic, stolid plodding, boring, tiresome, tedious, davus sum non Aedipus, deadly dull and boring, DDB.
Insipidity
N
insipidity, blandness, tastelessness, bland, void of taste, insipid, tasteless, gustless, savorless, ingustible, mawkish, milk and water, weak, stale, flat, vapid, fade, wishy-washy, mild, untasted.