To harm oneself in such a manner that leads to death
To be knocked off for knowing too much and likely to embarrass the Dear Leader over his war mongering ... not that we've got any dead WMD experts in mind here you understand... like say Dr._David_Kelly
Natures way of saying you have failed selection for planet urth.
To permanently put yourself out of your misery (possibly because you live in Bridgend).
See also: Su-wah-cide