The Collaborative International Dictionary of English v.0.48:

Astringency \As*trin"gen*cy\ ([a^]s*tr[i^]n"jen*s[y^]), n.
   The quality of being astringent; the power of contracting the
   parts of the body; that quality in medicines or other
   substances which causes contraction of the organic textures;
   as, the astringency of tannin.
   [1913 Webster]

WordNet (r) 3.0 (2006):

astringency
    n 1: a sharp astringent taste; the taste experience when a
         substance causes the mouth to pucker [syn: astringency,
         astringence]
    2: the ability to contract or draw together soft body tissues to
       check blood flow or restrict secretion of fluids [syn:
       astringency, stypsis]

Moby Thesaurus II by Grady Ward, 1.0:

97 Moby Thesaurus words for "astringency":
   Spartanism, abbreviation, acerbity, acidity, acidulousness,
   acridity, acridness, acrimony, asperity, astriction, astringence,
   austerity, authoritarianism, bite, bitingness, bitter pill,
   bitterness, bottleneck, causticity, cervix, circumscription,
   coarctation, compactedness, compaction, compression, compressure,
   concentration, condensation, consolidation, constriction,
   constringency, contraction, contracture, curtailment, cuttingness,
   decrease, demandingness, diminuendo, discipline, edge,
   exactingness, fierceness, gall, gall and wormwood, grimness, grip,
   hardness, harshness, hourglass, hourglass figure, inclemency,
   isthmus, keenness, knitting, meticulousness, mordacity, mordancy,
   narrow place, narrowing, neck, piquancy, poignancy, point,
   puckering, pungency, pursing, reduction, regimentation,
   rigid discipline, rigor, roughness, ruggedness, severity,
   sharpness, shortening, solidification, sourness, sternness, sting,
   stranglement, strangulation, striction, strictness, stricture,
   stridency, stringency, systole, tartness, teeth, toughness,
   trenchancy, ungentleness, vehemence, violence, virulence,
   wasp waist, wrinkling