The Collaborative International Dictionary of English v.0.48:

Inferiority \In*fe`ri*or"i*ty\, [Cf. F. inf['e]riorit['e].]
   The state of being inferior; a lower state or condition; as,
   inferiority of rank, of talents, of age, of worth.
   [1913 Webster]

         A deep sense of our own great inferiority. --Boyle.
   [1913 Webster]

WordNet (r) 3.0 (2006):

inferiority
    n 1: the state of being inferior [syn: inferiority, lower
         status, lower rank]
    2: an inferior quality [syn: inferiority, low quality] [ant:
       high quality, superiority]
    3: the quality of being a competitive disadvantage [syn:
       inferiority, unfavorable position]

Moby Thesaurus II by Grady Ward, 1.0:

128 Moby Thesaurus words for "inferiority":
   aberrance, aberrancy, aberration, abnormality, abnormity,
   amorphism, anomalism, anomalousness, anomaly, arrear, arrearage,
   arrears, badness, baseness, coarseness, commonness, damnability,
   decline, defalcation, default, defectiveness, deficiency, deficit,
   delinquency, derangement, deviation, difference, disability,
   disablement, disqualification, divergence, eccentricity,
   erraticism, evilness, failure, falling short, fourth-rateness,
   heteromorphism, humbleness, imbecility, immateriality,
   imperfection, improperness, inability, inaccuracy, inadequacy,
   inauspiciousness, incapability, incapacitation, incapacity,
   incompetence, incompetency, inconsequence, inconsequentiality,
   inconsiderableness, indifference, ineffectuality, inefficiency,
   ineptitude, inexpedience, infancy, inferiorness, insignificance,
   insufficiency, invalidity, irregularity, irrelevance, juniority,
   legal incapacity, littleness, low priority, lower status,
   lowliness, malevolence, marginality, meanness, mediocrity,
   minority, monstrosity, moral badness, negligibility, peccancy,
   pettiness, picayune, picayunishness, pokiness, poorness, puniness,
   reprehensibility, satellite status, second-rateness, secondariness,
   service, servitorship, shoddiness, short measure, shortage,
   shortcoming, shortfall, slightness, slump, smallness, subjecthood,
   subnormality, subordinacy, subordinate role, subordination,
   subservience, subserviency, superiority, teratism, third-rateness,
   underage, unfavorableness, unfitness, unhealthiness, unimportance,
   unimpressiveness, unkindness, unnaturalism, unnaturalness,
   unnoteworthiness, unpleasantness, unskillfulness, viciousness,
   wardship, wickedness, worthlessness