What does shallow mean in terms of one's charactor?
eg. Tim, you are so shallow. (I heard this from a TV programme)
Thank you.
It means that the person doesn't think very deeply about some things, perhaps they have a very simplistic view of life, or some specfic aspects of life. If you look up "shallow" and "deep" in a dictionary you should find definitions that aren't the usual ones about how much liquid there is!
For example, a man who likes women just because they are beautiful and doesn't consider their personality, their intellect, their achievements in life etc, might be said to be shallow. He's only interested in one aspect of a woman - her looks.
If I understand correctly what you are saying a superficial person wouldn't be shallow.
Superficial | Define Superficial at Dictionary.com
Shallow | Define Shallow at Dictionary.com
To me they are synonyms.