1520s, "obtain by force or compulsion; wrest away by oppressive means," from Latin extortus, past participle of extorquere "obtain by force," literally "to wrench out," from ex "out" (see ex-) + torquere "to twist" (from PIE root *terkw- "to twist"). Related: Extorted; extorting. As a past-participle adjective from early 15c.
It forms all or part of: contort; distort; extort; extortion; nasturtium; queer; retort; thwart; torch; torment; torque (n.) "rotating force;" torsion; tort; torticollis; tortuous; torture; truss.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit tarkuh "spindle;" Latin torquere "to twist;" Old Church Slavonic traku "band, girdle;" Old High German drahsil "turner," German drechseln "to turn on a lathe;" Old Norse þvert "across," Old English þweorh "transverse, perverse, angry, cross," Gothic þwairhs "angry."
"to extort entertainment from, to levy extractions upon," 1630s, apparently a phonetic spelling of Irish coisir "feast, entertainment." Related: Coshering (1570s).
"extortionate rent, rent raised to the highest possible limit, rent greater than any tenant can be expected to pay," especially of land-rents in Ireland, c. 1600, from rent (n.) + rack (v.1) in the otherwise obsolete sense of "extort or obtain by rapacity, raise (rent, etc.) above a fair level" (1550s).
Meaning "extort money from" is from 1670s. Of dyes or paints, "to be washed out," from 1862. Figuratively, of the heart, "to suffer anguish, feel pity or sorrow," late 14c.