aporetic (adj.)

"inclined to doubt," c. 1600, from French aporetique, from Greek aporetikos, from aporeein "to be at a loss, be without means or resources," from aporos "impassable, impracticable, very difficult; hard to deal with; at a loss," from a- "not, without" (see a- (3)) + poros "passage" (see pore (n.)).