1610s, "prevent by anticipative action," from Latin praecludere "to close, shut off; hinder, impede," from prae "before, ahead" (see pre-) + claudere "to shut" (see close (v.)). The more literal sense of "close, shut up, prevent access to" (1620s) probably is obsolete. Related: Precluded; precluding.
word-forming element making adjectives from verbs, meaning "pertaining to, tending to; doing, serving to do," in some cases from Old French -if, but usually directly from Latin adjectival suffix -ivus (source also of Italian and Spanish -ivo). In some words borrowed from French at an early date it has been reduced to -y (as in hasty, tardy).
<a href="https://www.etymonline.com/word/preclusive">Etymology of preclusive by etymonline</a>
Harper, D. (n.d.). Etymology of preclusive. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/preclusive