Question: Brass bands were being discussed today which naturally led to someone claiming to be *brassed off* about something, meaning disgruntled or annoyed. Does anyone know the origin of this expression? Michael Quinion over at [World Wide Words](http://www.worldwidewords.org/qa/qa-bra2.htm) suggests the phrase may have arisen from the Royal Navy's use of cleaning brasswork as a punishment, but that doesn't seem altogether convincing.

Answer: 
"Top Brass" meant command, because of their brass insignia. "Brassed Off" might mean told off by military authority, in a slang sense.
My understanding of the phrase is that it originated from the practise of sharpening an engineer's twist drill. The sharp cutting edge was dulled. Otherwise the sharp cutting edge would bite into the brass and chatter. If the cutting edge was removed it could cut into brass sheet or solid bar without any trouble. Hence the drill had been brassed off. I cannot see the connection between the usual understanding of the phrase as in hacked off, pissed off etc.