Friendly Fire is the disturbing term given to your own side (or allies) attempting to slot your arrse (probably and hopefully) by mistake.
Friendly Fire has been around as long as man has been giving his fellow man a shoeing. The first incidence of Friendly Fire was probably when Urgh and Ugg were throwing stones at their saber toothed lunch and Urgh accidentally hit Ugg with a rock. Back then there would not have been an independent inquest (not even legal aid for the compensation claim) so it was up to Ugg to deal with it himself.
Close combat accidental injury was originally called Friendly Stab but for some reason that term never really caught on.
Some nations are more likely to dish out Friendly Fire. Americans have been particularly bad over the decades. Famously during 1944 General George Patton threatened to take his 3rd Army out of the line against the Germans, turn it around 180' and destroy the 8th Army Air Force's airfields if they didn't stop bombing his lead elements. Recent Spam record in this area has been pretty bad as well. Equipped with Hellfire missiles, A-10 Warthog ground attack planes, fully automatic weapons, poor eyesight and a really poor enemy identification chart, they have slotted Candians, Brits, their own men (including a professional footballer who quit playing to be a US Ranger), civilians by the hundred, more of their own men, Italian secret service personel and a goodly number of foreign journalists.
Excuses that could be given in the event of a Friendly Fire incident: (please add)
- Honestly man, you looked like a raghead in this light!
- Thought you had heard the rumours about me boffing your wife.
- I'm American!