The Collaborative International Dictionary of English v.0.48:

Stuffiness \Stuff"i*ness\, n.
   The quality of being stuffy.
   [1913 Webster]

WordNet (r) 3.0 (2006):

stuffiness
    n 1: state of obstruction or stoppage or air in the nose or
         throat
    2: the quality of being close and poorly ventilated [syn:
       stuffiness, closeness]
    3: dull and pompous gravity [syn: stodginess, stuffiness]

Moby Thesaurus II by Grady Ward, 1.0:

203 Moby Thesaurus words for "stuffiness":
   Quakerishness, THI, airlessness, antiquation, aridity, aridness,
   authoritarianism, barrenness, bigotry, blind side, blind spot,
   blinders, bloodlessness, callowness, cantankerousness,
   censoriousness, characterlessness, childishness, closed mind,
   closeness, colorlessness, contrariness, cramped ideas, cussedness,
   deadness, dearth of ideas, demureness, demurity, difficultness,
   dismalness, disuse, dourness, dragginess, dreariness, dryness,
   dullness, dustiness, effeteness, emptiness, etiolation,
   false modesty, fanaticism, fetidity, fetidness, flatness,
   fogyishness, foulness, frowardness, frowst, frowstiness,
   frowziness, funkiness, fustiness, grandiloquence, heaviness,
   hideboundness, hollowness, humidity, humidness, illiberality,
   immaturity, imprudence, inadvisability, inanity, inattention,
   inconsideration, indiscreetness, indiscretion, inexcitability,
   inexpedience, infecundity, infertility, inflation, injudiciousness,
   insipidity, insipidness, insularism, insularity, irascibility,
   irrationality, jejunity, leadenness, lifelessness,
   little-mindedness, littleness, lowness of spirit, malodorousness,
   mauvaise honte, mean mind, meanness, mildew, moldiness, mugginess,
   must, mustiness, narrow sympathies, narrow views,
   narrow-mindedness, narrowness, nearsightedness, noisomeness,
   odium theologicum, odorousness, offensiveness, old-fashionedness,
   old-fogyishness, oppression, oppressiveness, orneriness,
   orotundity, out-of-dateness, overmodesty, paleness, pallor,
   parochialism, perverseness, perversite, perversity, pettiness,
   petty mind, pointlessness, pokiness, pomposity, pompousness,
   ponderousness, pontificality, pontification, priggishness,
   primness, prosaicism, prosaicness, prosaism, prosiness,
   provincialism, prudery, prudishness, puerility, purblindness,
   puritanicalness, putridness, rancidity, rancidness, rankness,
   reasonlessness, reastiness, recklessness, repulsiveness,
   rottenness, sanctimoniousness, sanctimony, self-importance,
   senselessness, shortsightedness, shut mind, slowness, smallness,
   smelliness, smugness, solemnity, spiritlessness, staidness,
   staleness, sterility, stickiness, stiff-neckedness, stiffness,
   stinkingness, stodginess, stolidity, straitlacedness, sulkiness,
   sullenness, superannuation, superficiality, swelter, tastelessness,
   tediousness, temperature-humidity index, thoughtlessness,
   turgidity, uncatholicity, uncreativeness, unfancifulness,
   unfashionableness, unimaginativeness, unintelligence,
   uninterestingness, unliveliness, unoriginality, unpoeticalness,
   unreason, unreasonableness, unsensibleness, unsoundness,
   unthoughtfulness, unwisdom, unwiseness, vapidity, vapidness,
   waywardness, witlessness, woodenness, wrongheadedness