"capable of effecting or tending to effect repairs," 1650s, with -ive + stem of Latin reparare "restore, repair" (see repair (v.1)). The meaning "pertaining to reparations, pertaining to the remedying of some wrong" is from 1690s.
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).
"to mend, put back in order, restore to a sound, good, or complete condition," mid-14c., reparen, from Old French reparer "repair, mend" (12c.) and directly from Latin reparare "restore, put back in order," from re- "again" (see re-) + parare "make ready, prepare" (from PIE root *pere- (1) "to produce, procure").
The sense of "make amends for injury by an equivalent, make good" is by 1560s. Related: Repaired; repairing.
<a href="https://www.etymonline.com/word/reparative">Etymology of reparative by etymonline</a>
Harper, D. (n.d.). Etymology of reparative. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/reparative