early 15c., proscriben, "write before or in front, prefix," from Latin proscribere "publish in writing" (literally "write in front of"), including "publish as having forfeited one's property; condemn, outlaw before the world," from pro "before" (see pro-) + scribere "to write" (from PIE root *skribh- "to cut").
From mid-15c. as "to exile, put out of the protection of the law" (implied in proscribed). By 1550s as "publish the name of as condemned to death and liable to confiscation of property." The meaning "denounce and prohibit (something) as wrong or dangerous" is recorded by 1620s.
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/proscriptive">Etymology of proscriptive by etymonline</a>
Harper, D. (n.d.). Etymology of proscriptive. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/proscriptive