NOUN (4)

1. the act of rejecting something;
- Example: "his proposals were met with rejection"

2. the state of being rejected;

3. (medicine) an immunological response that refuses to accept substances or organisms that are recognized as foreign;
- Example: "rejection of the transplanted liver"

4. the speech act of rejecting;

The Collaborative International Dictionary of English v.0.48:

Rejection \Re*jec"tion\ (r?-j?k"sh?n), n. [L. rejectio: cf. F.
   r['e]jection.]
   Act of rejecting, or state of being rejected.
   [1913 Webster]

WordNet (r) 3.0 (2006):

rejection
    n 1: the act of rejecting something; "his proposals were met
         with rejection"
    2: the state of being rejected [ant: acceptance]
    3: (medicine) an immunological response that refuses to accept
       substances or organisms that are recognized as foreign;
       "rejection of the transplanted liver"
    4: the speech act of rejecting