c. 1400, "act of beating or bruising; a bruise, an injury to the body without apparent wound or fracture," from Latin contusionem (nominative contusio) "a crushing, breaking, battering," in medical language, "a bruise," noun of action from past-participle stem of contundere "to beat, bruise, grind, crush, break to pieces," from assimilated form of com-, here perhaps an intensive prefix (see com-), + tundere "to beat" (see obtuse).
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/contusive">Etymology of contusive by etymonline</a>
Harper, D. (n.d.). Etymology of contusive. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/contusive