assimilative (adj.)

early 15c., in physiology, "absorb into and make part of the body," from Latin assimilatus, past participle of assimilare, assimulare "to make like, copy, imitate, assume the form of; feign, pretend," from assimilated form of ad "to" (see ad-) + simulare "make similar," from similis "like, resembling, of the same kind" (see similar).

The meaning "make alike, cause to resemble," and the intransitive sense "become incorporated into" are from 1620s. In linguistics, "bring into accordance or agreement in speech," from 1854. Related: Assimilated; assimilating.

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).