manipulative adj.

1827, "to handle skillfully by hand," a back-formation from manipulation. As "to manage by mental influence," especially for one's own purposes, is by 1864. Financial sense is from 1870. By 1949 it served as a euphemism for "masturbate." Related: Manipulated; manipulating.

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).