The Collaborative International Dictionary of English v.0.48:

Possessive \Pos*sess"ive\, a. [L. possessivus: cf. F.
   possessif.]
   Of or pertaining to possession; having or indicating
   possession.
   [1913 Webster]

   Possessive case (Eng. Gram.), the genitive case; the case
      of nouns and pronouns which expresses ownership, origin,
      or some possessive relation of one thing to another; as,
      Homer's admirers; the pear's flavor; the dog's
      faithfulness.

   Possessive pronoun, a pronoun denoting ownership; as, his
      name; her home; my book.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Possessive \Pos*sess"ive\, n.
   1. (Gram.) The possessive case.
      [1913 Webster]

   2. (Gram.) A possessive pronoun, or a word in the possessive
      case.
      [1913 Webster]

WordNet (r) 3.0 (2006):

possessive
    adj 1: serving to express or indicate possession; "possessive
           pronouns"; "the genitive endings" [syn: possessive,
           genitive]
    2: desirous of owning; "small children are so possessive they
       will not let others play with their toys"
    3: having or showing a desire to control or dominate; "a
       possessive parent"
    n 1: the case expressing ownership [syn: genitive, genitive
         case, possessive, possessive case]

Moby Thesaurus II by Grady Ward, 1.0:

43 Moby Thesaurus words for "possessive":
   acquisitive, ambitious for self, autistic, careerist, controlling,
   covetous, dominating, domineering, egotistical, grasping, greedy,
   individualistic, materialistic, narcissistic, niggardly,
   overbearing, personalistic, possessory, privatistic, proprietary,
   remote, self-absorbed, self-admiring, self-advancing, self-besot,
   self-centered, self-considerative, self-contained, self-devoted,
   self-esteeming, self-indulgent, self-interested, self-jealous,
   self-occupied, self-pleasing, self-seeking, self-serving,
   self-sufficient, selfish, stingy, ungenerous, ungiving,
   unyielding