definition of a priori:
(from Latin. translates to "from what came first") a process of arriving at a conclusion without the benefit of supporting evidence. Reasoning a priori uses an assumption as the basis for establishing a conclusion. The assumptions used to reason, a priori, commonly reflect a generally held belief.
a priori, as it might be used:
If a suspect with retained counsel cannot knowingly and intelligently waive his rights, then, a priori, a suspect without counsel cannot knowingly and intelligently waive those same rights.
a priori, in an example:
The car salesperson assured Ogden that his trade-in was worth only half the book value because of serious engine problems and extensive body rust. Ogden concluded, a priori, that the salesperson was lying based on his mistrust of the profession.