Nagoyakee san, is っぽい a special suffix? I have found it in other words (right now the only one I remember is 色っぽい).

Not sure what you mean by "special" but it's a suffix used quite often to express basically two things:

1. ～っぽい = containing much of ~. 水っぽい = watery.　粉（こな）っぽい = powdery.　

2. ～っぽい = showing a strong tendency of ~. こどもっぽい = chlidish. 飽（あ）きっぽい = fickle, capricious.　　荒（あら）っぽい = rough, violent, coarse.

That favorite word of yours falls under category #2.

Thank you very much.
Lol it is not really my favourite, it is just the one on my kanji flashcards that I am studying. All other cases that I had met before are not on my flashcards yet so I forgot them ;)

I always think of っぽい as the Japanese equivalent of the English "-ish." Like, he's "girl-ish" = 女っぽい, "boyish"=男っぽい, etc.