"to lower in dignity, lower the standing of, debase," c. 1600, perhaps from de- "down" + mean (adj.) and modeled on debase. It is indistinguishable in some uses from obsolete demean (Middle English, from Old French demener; see demeanor) which likely influenced it and might be its ultimate source. It was much-criticized in late 19c. by purists (Fitzedward Hall, etc.), and Century Dictionary (1897) reports "the word is avoided by scrupulous writers." Related: Demeaned; demeaning.
"lowering in character or repute," by 1848, present-participle adjective from demean (v.). Related: Demeaningly.
Proto-Indo-European root meaning "to change, go, move," "with derivatives referring to the exchange of goods and services within a society as regulated by custom or law" [Watkins].
It forms all or part of: amiss; amoeba; azimuth; common; commune; communicate; communication; communism; commute; congee; demean; emigrate; emigration; excommunicate; excommunication; immune; immutable; incommunicado; mad; mean (adj.1) "low-quality;" mew (n.2) "cage;" mews; migrate; migration; mis- (1) "bad, wrong;" mistake; Mithras; molt; Mstislav; municipal; munificent; mutable; mutant; mutate; mutation; mutatis mutandis; mutual; permeable; permeate; permutation; permute; remunerate; remuneration; transmutation; transmute; zenith.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit methati "changes, alternates, joins, meets;" Avestan mitho "perverted, false;" Hittite mutai- "be changed into;" Latin mutare "to change," meare "to go, pass," migrare "to move from one place to another," mutuus "done in exchange;" Old Church Slavonic mite "alternately;" Czech mijim "to go by, pass by," Polish mijać "avoid;" Gothic maidjan "to change."
"a person's facial expression," 1510s, probably a shortening of Middle English demean "bearing, demeanor" (see demeanor) and influenced by French mine "appearance, facial expression," which is of unknown origin, possibly Celtic (compare Breton min "beak, muzzle, nose," Irish men "mouth").
late 15c., demenure, "conduct, management, treatment, behavior toward someone," from obsolete Middle English demean, demeinen "to handle, manage, conduct," later "behave in a certain way, conduct oneself" (early 14c.), from Old French demener (11c.) "to guide, conduct; to live, dwell," from de- "completely" (see de-) + mener "to lead, direct," from Latin minari "to threaten," in Late Latin "to drive (a herd of animals);" see menace (n.). Meaning "behavior, bearing, deportment" is from late 15c. Spelling changed by influence of nouns in -or, -our.