If "potential" is "having or showing the capacity to become or develop into something in the future"; then *Pretential* is the *potential to have potential*.
Example; If you study well, you have POTENTIAL.
If you aren't bothering to study, but you have the right teachers, books, notes, etc.; then you have PRETENTIAL
Person 1: You've got a great teacher, the textbook's got all the information, and you have every other possible tool you could need! You've just got so much potential!
Person 2: I don't have potential, I'm not studying yet!
Person 1: Yes you do...
Person 2: No, I only have *PREtential*
but this word could be used in any context :P