The Collaborative International Dictionary of English v.0.48:

Tightness \Tight"ness\, n.
   The quality or condition of being tight.
   [1913 Webster]

WordNet (r) 3.0 (2006):

tightness
    n 1: a state occasioned by scarcity of money and a shortage of
         credit [syn: stringency, tightness]
    2: a tight feeling in some part of the body; "he felt a
       constriction in her chest"; "she felt an alarming tightness
       in her chest"; "emotion caused a constriction of his throat"
       [syn: constriction, tightness]
    3: the spatial property of being crowded together [syn:
       concentration, density, denseness, tightness,
       compactness] [ant: dispersion, distribution]
    4: extreme stinginess [syn: meanness, minginess,
       niggardliness, niggardness, parsimony,
       parsimoniousness, tightness, tightfistedness,
       closeness]
    5: lack of movement or room for movement [syn: tightness,
       tautness] [ant: looseness, play]

Moby Thesaurus II by Grady Ward, 1.0:

107 Moby Thesaurus words for "tightness":
   Jim Crow, adhesiveness, alien, apartheid, avarice, bullheadedness,
   cheapness, chinchiness, chintziness, closefistedness, closeness,
   cohesiveness, color bar, confinement, consistency, crowdedness,
   division, ethnocentrism, exclusiveness, exiguity, fewness,
   firmness, foreigner, gluiness, glutinosity, gumminess, hair,
   hairbreadth, hairsbreadth, hardfistedness, hoarding, illiberality,
   incapaciousness, incommodiousness, infrequency, insularity,
   insulation, isolation, know-nothingism, limitation, meagerness,
   miserliness, narrow gauge, narrowness, nearness, niggardliness,
   obstinacy, out-group, outcast, outsider, parochialism, paucity,
   penny-pinching, persistence, persistency, persona non grata,
   quarantine, race hatred, racial segregation, rarity, renitence,
   renitency, restrictedness, restriction, retention, rigidity,
   rigidness, rigor, scantiness, scarcity, scrimpiness, seclusion,
   segregation, separation, skimpiness, slenderness, smallness,
   snobbishness, snugness, sparseness, sparsity, starchiness,
   stick-to-itiveness, stickiness, stiffness, stinginess, straitness,
   stranger, strictness, stringency, stubbornness, tackiness,
   tautness, tenaciousness, tenacity, tenseness, tension, tensity,
   thinness, tight purse strings, tight squeeze, tightfistedness,
   toughness, ungenerosity, viscidity, viscosity, xenophobia