I think that's みんなのあだ, actually. One thing that sort of carries the idea might be "public enemy", but it doesn't work there... barring better suggestions, you could use "fiend".
LaC said: I think that's みんなのあだ, actually. One thing that sort of carries the idea might be "public enemy", but it doesn't work there... barring better suggestions, you could use "fiend".
I think you're right, according to my dictionaries a possible meaning would be 恨みのある相手, i.e. enemy, foe. I don't fully like "public enemy" in this context, but I can't think of a better translation right now.
I suppose the joke has its roots in the Chinese Zodiac and the fact that the cat isn't in it (like anyone which has read/watched Fruits Basket knows).