Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
ascriptīvus (adscr-), a, um, adj. [ascribo, II.], enrolled as a (supernumerary) soldier (cf. ascripticius and accensus): Idem istuc aliis adscriptivis ad legionem fieri solet, Plaut. Men. 1, 3, 2; Varr. L. L. 7, § 56 Müll.