Correct spelling of numnut. Normally used as an insult meaning idiot. However, also implies that the recipient is a coward, sterile or impotent. A combination of numb and nut, where nut is a slang for testicle. In other words, a man who cannot feel his testicles and acts accordingly.
"Are you lookin at me, numbnut? Cause if you are, I'm going to damage what's left of your courage."
To make a series of mistakes, so heinously incorrect and far reaching in effect such that the result defies description. The phrase is a combination of other phrases meaning mistake, 'screw the pooch', 'royal fuckup' as well as a group sex form of fuck, 'clusterfuck'. The phase can also be used as a verb, 'clusterfucking the royal pooch.'
Not supporting the public transportation vehicle information system standard on busses was a royal pooch clusterfuck for the public transportation authority.