Latin adverb and preposition of separation in space, meaning "down from, off, away from," and figuratively "concerning, by reason of, according to;" from PIE demonstrative stem *de- (see to). Also a French preposition in phrases or proper names, from the Latin word.

mid-14c., of God, a king., etc., "make gracious allowance" for human frailty, etc.; late 14c., "yield deferentially," from Old French condescendere (14c.) "to agree, consent, give in, yield, come down from one's rights or claims," and directly from Late Latin condescendere "to let oneself down, stoop," in Medieval Latin "be complaisant or compliant," from assimilated form of Latin com "with, together" (see con-) + descendere "to descend," literally "climb down," from de "down" (see de-) + scandere "to climb," from PIE root *skand- "jump" (see scan (v.)).

Sense of ""voluntarily waive ceremony or dignity proper to one's superior position or rank and willingly assume equality with inferiors" is from early 15c. Generally a positive word in Middle English; the modern, negative sense is from the notion of a mere show or assumed air of condescending (compare sense evolution in patronize). Also in Middle English "give one's consent; come to mutual agreement; make a concession."

also deaccession, "remove an entry for an item from the register of a museum, library, etc." (often a euphemism for "to sell"), by 1968, from de- "off, away" + accession, which had been used since 1887 in library publications as a verb meaning "to add to a catalogue." Related: De-accessioned; de-accessioning.

also de-activate, "render inactive or less active," 1904, from de- "do the opposite of" + activate. Related: Deactivated; deactivating; deactivation.

"removal of an amino group," 1912, from de- + amine + noun ending -ation.

"to render un-English or less English," 1876; see de- "do the opposite of" + anglicize. Related: De-anglicised; de-anglicized; de-anglicizing.

"remove (someone's) trousers as a punishment or joke," 1902 ["An American at Oxford"], British English college slang, from de- "off, away" + bag (n.). Related: Debagged; debagging.

"undeceive, disabuse," 1919; see de- "do the opposite of" + bamboozle.

"to strip the bark off" (a tree), 1742, from de- "from, off" + bark (n.1). Related: Debarked; debarking.

1560s, "lower in position, rank, or dignity, impair morally," from de- "down" + base (adj.) "low," on analogy of abase (or, alternatively, from obsolete verb base "to abuse"). From 1590s as "lower in quality or value" (of currency, etc.), "degrade, adulterate." Related: Debased; debasing; debasement.