1. 
[syn: suicide, self-destruction, self-annihilation]
2.  the act of destroying yourself; 
- Example: "his insistence was pure self-destruction"
The Collaborative International Dictionary of English v.0.48:
Self-destruction \Self`-de*struc"tion\, n.
   The destruction of one's self; self-murder; suicide.
   --Milton.
   [1913 Webster]
WordNet (r) 3.0 (2006):
self-destruction
    n 1: the act of killing yourself; "it is a crime to commit
         suicide" [syn: suicide, self-destruction, self-
         annihilation]
    2: the act of destroying yourself; "his insistence was pure
       self-destruction"