fratricide

noun4

1. •
   The killing of one's brother (or sister).
2. •
   The intentional or unintentional killing of a comrade in arms.

   • From January on, Third Army also spent a good deal of energy trying to solve the problem of fratricide, the killing or injuring of one's own forces by what is ironically called 'friendly fire,'[…] — 1999
3. •
   A person who commits fratricide.
4. •
   The undesirable situation where the separate missiles from a MIRV interfere with each other as they explode.