A general hint for figuring out whether in fact I have made something up for my own devious amusement is that, when I do, I have a tendency to include meandering faux-etymologies.
FWIW, the majority of references to snurge on a google search, if not referring to a racehorse, seem to use it as a noun, with a meaning close to the following (taken from the 'Word Detective' site)
A “snurge�? is a despicable person, especially a sneaky little toady whose greatest joy comes from ratting out other people to the teacher, boss or other authority figure in order to curry favor with those in power.
It appears to have originated as a slang term in British public schools.