Online Etymology Dictionary

contingency (n.): 1560s, "quality of being contingent," from contingent + -cy. Meaning "a chance occurrence" is from 1610s.
contingent (adj.): late 14c., from Old French contingent or directly from Latin contingentem (nominative contingens) "happening, touching," present participle of contingere "to touch" (see contact). The noun is from 1540s, "thing happening by chance;" as "a group forming part of a larger group" from 1727.
continual (adj.): early 14c., continuell, from Old French continuel (12c.), from Latin continuus (see continue). That which is continual is that which is either always going on or recurs at short intervals and never comes to an end; that which is continuous is that in which there is no break between the beginning and the end. Related: Continually (c. 1300, contynuelliche).
continuance (n.): mid-14c., "a keeping up, a going on," from Old French continuance (13c.), from continuer (see continue).
continuation (n.): late 14c., from Old French continuation (13c.), or directly from Latin continuationem (nominative continuatio), noun of action from continuat-, past participle stem of continuare (see continue).
continue (v.): mid-14c., contynuen, from Old French continuer (13c.), from Latin continuare "join together, connect, make or be continuous," from continuus "uninterrupted," from continere (intransitive) "to be uninterrupted," literally "to hang together" (see contain). Related: Continued; continuing.
continuity (n.): early 15c., from Middle French continuité, from Latin continuitatem (nominative continuitas), from continuus (see continue). Cinematographic sense is recorded from 1921, American English.
continuous (adj.): 1640s, from French continueus or directly from Latin continuus "uninterrupted, hanging together" (see continue). Related: Continuously.
continuum (n.): 1640s, from Latin continuum "a continuous thing," neuter of continuus (see continue). The plural is continua.
contort (v.): early 15c., from Latin contortus, past participle of contorquere "to whirl, twist together," from com- "together" or intensive (see com-) + torquere "to twist" (see torque (n.)). Related: Contorted; contorting.
contortion (n.): early 15c., from Middle French contorsion or directly from Latin contortionem (nominative contorsio), noun of action from past participle stem of contorquere (see contort).
contortionist (n.): 1841, from contortion + -ist.
contour (n.): 1660s, a term in painting and sculpture, from French contour "circumference, outline," from Italian and Medieval Latin contornare "to go around," from Latin com-, intensive prefix (see com-), + tornare "to turn (on a lathe);" see turn (v.).

First recorded application to topography is from 1769. Earlier the word was used to mean "bedspread, quilt" (early 15c.) in reference to its falling over the sides of the mattress. Related: Contoured. Contour line in geography is from 1844.
contra: mid-14c., from Latin contra (prep. and adv.) "against," originally "in comparison with," ablative singular feminine of *com-teros, from Old Latin com "with, together" (see com-) + -tr, zero degree of the comparative suffix -ter-.
Contra (n.): 1981, "anti-Sandinista Nicaraguan," short for Spanish contrarrevolucionario "counter-revolutionary."
contra dance: 1803, from French contre-danse, altered from English country dance by folk etymology from French contra "against," suggested by the arrangement of the partners in the dance. The dances and the name were taken up in France c. 1720s and from there passed to Spain and Italy (Spanish, Italian contra danza) then back to English.
contra-: word-forming element meaning "against, in opposition," from Latin adverb and preposition contra "against" (see contra). The Latin word was used as a prefix in Late Latin. In French, it became contre- and passed into English as counter-. The Old English equivalent was wiðer (surviving in withers and widdershins), from wið "with, against."
contraband (n.): 1520s, "smuggling;" 1590s, "smuggled goods;" from Middle French contrebande "a smuggling," from older Italian contrabando (modern contrabbando) "unlawful dealing," from Latin contra "against" (see contra) + Medieval Latin bannum, from Frankish *ban "a command" or some other Germanic source (see ban (v.)).
contraception (n.): "birth control," coined 1886 from Latin contra (see contra) + ending from conception.
contraceptive: 1891 (n.), 1918 (adj.), from stem of contraception + -ive.
contract (v.): late 14c., "make narrow, draw together;" early 15c. "make an agreement;" from Middle French contracter, from Latin contractus, past participle of contrahere "to draw together, combine, make an agreement" (see contract (n.)). Related: Contracted; contracting.
contract (n.): early 14c., from Old French contract (Modern French contrat), from Latin contractus "a contract, agreement," from past participle of contrahere "to draw together," metaphorically, "to make a bargain," from com- "together" (see com-) + trahere "to draw" (see tract (n.1)). U.S. underworld sense of "arrangement to kill someone" first recorded 1940.
contracted (adj.): c. 1600, "agreed upon," also "shrunken, shortened," past participle adjective from contract (v.).
contractile (adj.): 1706, from French contractile, from Latin contract-, past participle stem of contrahere (see contract (n.)). Related: Contractility. Contractile vacuole is from 1877.
contraction (n.): late 14c., "action of making a contract" (especially of marriage), also "action of shrinking or shortening," from Old French contraction (13c.), or directly from Latin contractionem (nominative contractio), noun of action from past participle stem of contrahere (see contract (n.)). Meaning "action of acquiring (a disease) is from c. 1600. Grammatical sense is from 1706; meaning "a contracted word or words" is from 1755. Contractions of the uterus in labor of childbirth attested from 1962.
contractor (n.): 1540s, "one who enters into a contract," from Late Latin contractor, agent noun from past participle stem of Latin contrahere (see contract (n.)); specifically of "one who enters into a contract to provide work, services, or goods" from 1724.
contractual (adj.): 1827, from Latin contractus (see contract (n.)) + -al (1).
contracture (n.): 1650s, from French contracture, from Latin contractura "a drawing together," from contractus, past participle of contrahere (see contract (n.)).
contradict (v.): 1570s, "speak against," also "assert the contrary" (1580s), from Latin contradictus, past participle of contradicere (see contradiction). Related: Contradicted; contradicting; contradictive.
contradiction (n.): late 14c., from Old French contradiction or directly from Latin contradictionem (nominative contradictio) "a reply, objection, counterargument," noun of action from past participle stem of contradicere, in classical Latin contra dicere "to speak against," from contra "against" (see contra) + dicere "to say, speak" (see diction).
contradictory (adj.): 1530s, "mutually opposed, at variance," from Late Latin contradictorius "containing a contradiction or objection," from contradictus, past participle of contradicere (see contradiction). Meaning "fond of contradicting" is from 1891. Used earlier as a noun (late 14c.).
contradistinction (n.): 1640s, from contra- + distinction.
contrail (n.): 1945, from condensation trail.
contraindicate (v.): 1660s, from contra- + indicate. Related: Contraindicated; contraindication (1620s).
contralateral (adj.): 1882, from contra- + lateral.
contralto (n.): "lowest female voice," 1730, from Italian contralto; see contra- "against, opposite" + alto. The part next above the alto.
contraposition (n.): 1550s, from Late Latin contrapositionem (nominative contrapositio), noun of action from past participle stem of contraponere, from contra "against" (see contra) + ponere "to put, place" (past participle positus; see position (n.)).
contrapositive (adj.): 1858 (implied in contrapositively), from Latin contraposit-, past participle stem of contraponere (see contraposition) + -ive.
contrapposto (n.): 1903, from Italian contrapposto, past participle of contrapporre, from Latin contraponere (see contraposition).
contraption (n.): 1825, western England dialect, origin obscure, perhaps from con(trive) + trap, or deception.
contrapuntal (adj.): 1845, from Italian contrapunto "counterpoint," also "backstitch," from contra "against" (see contra) + punto "point" (see point (n.)). Musical use is from Medieval Latin cantus contrapunctis. Compare counterpoint. Related: Contrapuntally.
contrarian (n.): 1963, from contrary + -ian.
To be in opposition is not to be a nihilist. And there is no decent or charted way of making a living at it. It is something you are, and not something you do. [Christopher Hitchens, "Letters to a Young Contrarian," 2001]
contrariety (n.): late 14c., from Old French contrarieté, from Late Latin contrarietatem (nominative contrarietas) "opposition," noun of quality from contrarius (see contrary).
contrariness (n.): late 14c., "state of being contrary," from contrary + -ness. Meaning "fondness of opposition" is from 1640s.
contrary (adj.): mid-14c., from Anglo-French contrarie, from Latin contrarius "opposite, opposed," from contra "against" (see contra).
If we take the statement All men are mortal, its contrary is Not all men are mortal, its converse is All mortal beings are men, & its opposite is No men are mortal. The contrary, however, does not exclude the opposite, but includes it as its most extreme form. Thus This is white has only one opposite, This is black, but many contraries, as This is not white, This is coloured, This is dirty, This is black; & whether the last form is called the contrary, or more emphatically the opposite, is usually indifferent. But to apply the opposite to a mere contrary (e.g. to I did not hit him in relation to I hit him, which has no opposite), or to the converse (e.g. to He hit me in relation to I hit him, to which it is neither contrary nor opposite), is a looseness that may easily result in misunderstanding; the temptation to go wrong is intelligible when it is remembered that with certain types of sentence (A exceeds B) the converse & the opposite are identical (B exceeds A). [Fowler]
As a noun from late 13c. Related: Contrarily; contrariwise.
Contras (n.): see Contra.
contrast (v.): 1690s, from French contraster (Old French contrester), modified by or from Italian contrastare "stand out against, strive, contend," from Vulgar Latin *contrastare "to withstand," from Latin contra "against" (see contra) + stare "to stand," from PIE root *stā- "to stand" (see stet).

Middle English had contrest "to fight against, to withstand," which became extinct. Modern word re-introduced as an art term. Related: Contrasted; contrasting; contrastive.
contrast (n.): 1711, from contrast (v.).
contrasting (adj.): 1715, present participle adjective from contrast (v.). From 1680s as a verbal noun.
contravene (v.): 1560s, from Middle French contravenir "to transgress, decline, depart," from Late Latin contravenire "to come against," in Medieval Latin "to transgress," from Latin contra "against" (see contra) + venire "to come" (see venue). Related: Contravened; contravening.