1.  A bend, turn, or curve; curvature; flexure. [1913 Webster]
"Through lanes, and crooks, and darkness." [1913 Webster]

2.  Any implement having a bent or crooked end. [1913 Webster]
"He left his crook, he left his flocks." [1913 Webster]

3.  A pothook. Sir W. Scott. [1913 Webster]

4.  An artifice; trick; tricky device; subterfuge. [1913 Webster]
"For all yuor brags, hooks, and crooks." [1913 Webster]

5.  A small tube, usually curved, applied to a trumpet, horn, etc., to change its pitch or key. [1913 Webster]

6.  A person given to fraudulent practices; an accomplice of thieves, forgers, etc. [1913 Webster]

1.  To turn from a straight line; to bend; to curve. [1913 Webster]
"Crook the pregnant hinges of the knee." [1913 Webster]

2.  To turn from the path of rectitude; to pervert; to misapply; to twist. [1913 Webster]
"There is no one thing that crooks youth more than such unlawfull games." [1913 Webster]
"What soever affairs pass such a man's hands, he crooketh them to his own ends." [1913 Webster]

   To bend; to curve; to wind; to have a curvature. Phaer. [1913 Webster]
"Their shoes and pattens are snouted, and piked more than a finger long, crooking upwards." [1913 Webster]

crook, n., v., & adj.
--n.
1 the hooked staff of a shepherd or bishop.
2 a a bend, curve, or hook. b anything hooked or curved.
3 colloq. a a rogue; a swindler. b a professional criminal.
--v.tr. & intr. bend, curve.
--adj.
1 crooked.
2 Austral. & NZ colloq. a unsatisfactory, out of order; (of a person) unwell, injured. b unpleasant. c dishonest, unscrupulous. d bad-tempered, irritable, angry.

Idiom:
crook-back a hunchback. crook-backed hunchbacked. go crook (usu. foll. by at, on) Austral. & NZ colloq. lose one's temper; become angry.

Derivative:
crookery n.

Etymology:
ME f. ON kr{oacute}kr hook

N  thief, robber, homo triumliterarum, pilferer, rifler, filcher, plagiarist, spoiler, depredator, pillager, marauder, harpy, shark, land shark, falcon, mosstrooper, bushranger, Bedouin, brigand, freebooter, bandit, thug, dacoit, pirate, corsair, viking, Paul Jones, buccaneer, buccanier, piqueerer, pickeerer, rover, ranger, privateer, filibuster, rapparee, wrecker, picaroon, smuggler, poacher, abductor, badger, bunko man, cattle thief, chor, contrabandist, crook, hawk, holdup man, hold-up, jackleg, kidnaper, rustler, cattle rustler, sandbagger, sea king, skin, sneak thief, spieler, strong-arm man, highwayman, Dick Turpin, Claude Duval, Macheath, footpad, sturdy beggar, cut purse, pick purse, pickpocket, light-fingered gentry, sharper, card sharper, skittle sharper, thimblerigger, rook, Greek, blackleg, leg, welsher, defaulter, Autolycus, Jeremy Diddler, Robert Macaire, artful dodger, trickster, swell mob, chevalier d'industrie, shoplifter, swindler, peculator, forger, coiner, fence, receiver of stolen goods, duffer, smasher, burglar, housebreaker, cracksman, magsman, Bill Sikes, Jack Sheppard, Jonathan Wild, gang, gang of thieves, theft ring, organized crime, mafia, the Sicilian Mafia, the mob, la cosa nostra, Dillinger, Al Capone, Robin Hood.

N  curvature, curvity, curvation, incurvature, incurvity, incurvation, bend, flexure, flexion, flection, conflexure, crook, hook, bought, bending, deflection, deflexion, inflection, inflexion, concameration, arcuation, devexity, turn, deviation, detour, sweep, curl, curling, bough, recurvity, recurvation, sinuosity, kink, carve, arc, arch, arcade, vault, bow, crescent, half-moon, lunule, horseshoe, loop, crane neck, parabola, hyperbola, helix, spiral, catenary, festoon, conchoid, cardioid, caustic, tracery, arched ceiling, arched roof, bay window, bow window, sine curve, spline, spline curve, spline function, obliquity, curved, curviform, curvilineal, curvilinear, devex, devious, recurved, recurvous, crump, bowed, vaulted, hooked, falciform, falcated, semicircular, crescentic, sinusoid, parabolic, paraboloid, luniform, lunular, semilunar, conchoidal, helical, double helical, spiral, kinky, cordiform, cordated, cardioid, heart shaped, bell shaped, boat shaped, crescent shaped, lens shaped, moon shaped, oar shaped, shield shaped, sickle shaped, tongue shaped, pear shaped, fig shaped, kidney-shaped, reniform, lentiform, lenticular, bow-legged, oblique, circular, aduncated, arclike, arcuate, arched, beaked, bicorn, bicornuous, bicornute, clypeate, clypeiform, cymbiform, embowed, galeiform, hamate, hamiform, hamous, hooked, linguiform, lingulate, lobiform, lunate, navicular, peltate, remiform, rhamphoid, rostrate, rostriferous, rostroid, scutate, scaphoid, uncate, unguiculate, unguiform.

VB  be curved curve, sweep, sway, swag, sag, deviate, curl, turn, reenter, render curved, flex, bend, curve, incurvate, inflect, deflect, scatter, refract (light), crook, turn, round, arch, arcuate, arch over, concamerate, bow, curl, recurve, frizzle, rotundity, convexity.

VB  alter one's course, deviate, depart from, turn, trend, bend, curve, swerve, heel, bear off, gybe, wear, intervert, deflect, divert, divert from its course, put on a new scent, shift, shunt, draw aside, crook, warp, stray, straggle, sidle, diverge, tralineate, digress, wander, wind, twist, meander, veer, tack, divagate, sidetrack, turn aside, turn a corner, turn away from, wheel, steer clear of, ramble, rove, drift, go astray, go adrift, yaw, dodge, step aside, ease off, make way for, shy, fly off at a tangent, glance off, wheel about, face about, turn to the right about, face to the right about, waddle, go out of one's way, lose one's way.

N  bad man, wrongdoer, worker of iniquity, evildoer, sinner, the wicked, bad example, villain, rascal, scoundrel, miscreant, budmash, caitiff, wretch, reptile, viper, serpent, cockatrice, basilisk, urchin, tiger, monster, devil, devil incarnate, demon in human shape, Nana Sahib, hellhound, hellcat, rakehell, bad woman, jade, Jezebel, scamp, scapegrace, rip, runagate, ne'er-do-well, reprobate, scalawag, scallawag, rou_e, rake, Sadist, skeesicks, skeezix, limb, one who has sold himself to the devil, fallen angel, ame damnee, vaurien, mauvais sujet, loose fish, sad dog, rounder, lost sheep, black sheep, castaway, recreant, defaulter, prodigal, rough, rowdy, hooligan, tough, ugly customer, mean mother, ruffian, bully, meanie, Jonathan Wild, hangman, incendiary, arsonist, fire bug, thief, murderer, terrorist, culprit, delinquent, crook, hoodlum, hood, criminal, thug, malefactor, offender, perpetrator, perp, disorderly person, misdemeanant, outlaw, scofflaw, vandal, felon, (convicted criminal), criminal, convict, prisoner, inmate, jail bird, ticket of leave man, multiple offender, blackguard, polisson, loafer, sneak, rapscallion, rascallion, cullion, mean wretch, varlet, kern, ame-de-boue, drole, cur, dog, hound, whelp, mongrel, lown, loon, runnion, outcast, vagabond, rogue, ronian, scum of the earth, riffraff, Arcades ambo, Int, sirrah!, Acherontis pabulum, gibier de potence.

by hook or by crook, shepherd's crook