The Collaborative International Dictionary of English v.0.48:

Recessive \Re*ces"sive\ (r[-e]*s[e^]s"s[i^]v), a.
   1. Going back; receding.
      [1913 Webster]

   2. (Genetics) Not appearing in the phenotype unless both
      alleles of the organism have the same trait; -- of genetic
      characteristics, or of the genes coding for such
      characteristics, in diploid organisms. Opposite of
      dominant; hemophilia is a recessive trait.
      [PJC]

The Collaborative International Dictionary of English v.0.48:

Recessive \Re*ces"sive\ (r[-e]*s[e^]s"s[i^]v), n. (Genetics)
   A genetic trait determined by a recessive[2] allele; a trait
   not appearing in the phenotype unless both chromosomes of the
   organism have the same allele; also, an allele which is
   recessive[2].
   [PJC]

WordNet (r) 3.0 (2006):

recessive
    adj 1: of or pertaining to a recession [syn: recessionary,
           recessive]
    2: (of genes) producing its characteristic phenotype only when
       its allele is identical [ant: dominant]
    n 1: an allele that produces its characteristic phenotype only
         when its paired allele is identical [syn: recessive
         allele, recessive]

Moby Thesaurus II by Grady Ward, 1.0:

21 Moby Thesaurus words for "recessive":
   atavistic, reactionary, recedent, recessional, recessionary,
   recidivist, recidivous, regressive, retroactive, retrocedent,
   retrocessive, retrograde, retrogressive, retrorse, retroverse,
   returnable, reversible, reversional, reversionary, revertible,
   revulsionary