Is it ensure, insure, or assure?
c.1200, "gentle, quiet, unaggressive; benevolent, kind; courteous, humble, unassuming;" of a woman, "modest," from a Scandinavian source (cf. Old Norse mjukr "soft, pliant, gentle"), from Proto-Germanic *meukaz (cf. Gothic muka-modei "humility," Dutch muik "soft"), of uncertain origin, perhaps from PIE *meug- "slippery, slimy." In the Bible, it translates Latin mansuetus from Vulgate (see mansuetude). Sense of "submissive" is from mid-14c.
"those who are meek," c.1200, from meek (adj.).