"act of taking more than one's due," 1590s, from Latin arrogationem (nominative arrogatio) "a taking to oneself," noun of action from past-participle stem of arrogare "to claim for oneself" (see arrogate).
1711, "an exclusive party of persons; a small set, especially one associating to arrogate power or privilege," from obsolete French clique, which meant originally (14c.) "a sharp noise," also "latch, bolt of a door," from Old French cliquer "click, clatter, crackle, clink," 13c., echoic. Apparently this word was at one time treated in French as the equivalent of claque (q.v.) and partook of that word's theatrical sense.
early 15c., "to arrogate, take upon oneself," from Latin assumere, adsumere "to take up, take to oneself, take besides, obtain in addition," from ad "to, toward, up to" (see ad-) + sumere "to take," from sub "under" (see sub-) + emere "to take," from PIE root *em- "to take, distribute."
Meaning "to suppose, to take for granted without proof as the basis of argument" is first recorded 1590s; that of "to take or put on fictitiously" (an appearance, etc.) is from c. 1600. Related: Assumed; assuming. Early past participle was assumpt. In rhetorical usage, assume expresses what the assumer postulates, often as a confessed hypothesis; presume expresses what the presumer really believes. Middle English also had assumpten "to receive up into heaven" (especially of the Virgin Mary), from the Latin past participle.