apodictic (adj.)

also apodeictic, "clearly demonstrated," 1650s, from Latin apodicticus, from Greek apodeiktikos, from apodeiktos, verbal adjective of apodeiknynai "to show off, demonstrate, show by argument, point out, prove," literally "to point away from" (other objects, at one), from apo "off, away" (see apo-) + deiknynai "to show" (from PIE root *deik- "to show"). Related: Apodictical (1630s); apodictically (1610s).