"serving to close, having the function of closing," 1867, from Latin occlus-, past-participle stem of occludere (see occlude) + -ive.
Entries linking to occlusive
occlude v.
"to shut up or stop up so as to prevent anything from passing through," 1590s, from Latin occludere (past participle occlusus) "shut up, close up," from assimilated form of ob "in front of, against" (see ob-) + claudere "to shut, close" (see close (v.)). Of teeth, "come in contact with another tooth," 1888. Related: Occluded; occluding.
-ive
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).