Originally Posted by Cheez
Face is slang for an outstanding person. I am not sure why. Perhaps it's because you always find an image of someone's face (like the Queen) engraved on a coin?....?? It's usually Royalty or someone famous.
Now, a heel is a dishonest, contemptible person. Again, I will be shooting in the dark here but I think it refers to someone whose presence is unwanted (he is always at your heels).
Also, when you bring a dog to heel, he listens and it's a sign of obedience. Maybe that has something to do with the slang word "heel"...superiority of one over the other?
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