I think the dictionary entry says that "greyhound" is a noun. It's translation ("борзая") is obviously a noun too. It happen to be derived from a femenine adjective.

That is n describes the word "greyhound" and the "f adj." part belongs to the word "борзая". "f adj." doesn't necessary mean that "борзая" can be used as an adjective, it just explains that it is feminine and derived from an adjective