If this was Pyramid I wouldn't allow it (because it conveys the "essence of the word") but I would accept it for Password. Here is what the Million Dollar Password rules say:
It is allowable to repeat a small part of the Password as part of a clue, as long as it is not the entire main root. For example, although "foot" and "ball" would not be allowed as clues for the Password "football", the clue "baseball" would be allowed. "Day" would not be allowed as a clue for "Monday", but "Sunday" would be allowed. "Strawberry" would be allowed as a clue for "blackberry", since the repeated part "berry" is not the entire main root of "blackberry".
So, I take this to mean that "Phil" or "Delphia" (if that was a real word) wouldn't work but "Phillies", an established proper noun, is acceptable.