I believe that is Non Official Cover Agent. Basically, a intelligence agent that, well, they do a lot of stuff, but from my understanding, not having worked in the system, they mostly handle informants and turn sources and handle intelligence gathering. A spy. It's non-official cover in the sense that they don't come as a diplomat attache or anything of the sorts but go there and present themselves as a private individual. Some countries, not sure of the case of Canada, you can't share your real job with your friends or family but have a cover story instead. They mostly present their real name as well, since it's hard to produce fake personas, hence... his original post.

Much less glamourous than James Bond, but I believe it's an.. interesting job.

This is a good summary. Most people I knew didn't know and if they knew anything it was only a hint here or there and most assumed I was doing sigint work.