The Collaborative International Dictionary of English v.0.48:

Zigzag \Zig"zag`\, n. [F. zigzag, G. zickzack, from zacke,
   zacken, a dentil, tooth. Cf. Tack a small nail.]
   [1913 Webster]
   1. Something that has short turns or angles.
      [1913 Webster]

            The fanatics going straight forward and openly, the
            politicians by the surer mode of zigzag. --Burke.
      [1913 Webster]

   2. (Arch.) A molding running in a zigzag line; a chevron, or
      series of chevrons. See Illust. of Chevron, 3.
      [1913 Webster]

   3. (Fort.) See Boyau.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Zigzag \Zig"zag`\, a.
   Having short, sharp turns; running this way and that in an
   onward course.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Zigzag \Zig"zag`\, v. t. [imp. & p. p. Zigzagged; p. pr. & vb.
   n. Zigzagging.]
   To form with short turns.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Zigzag \Zig"zag`\, v. i.
   To move in a zigzag manner; also, to have a zigzag shape.
   --R. Browning.
   [1913 Webster]

WordNet (r) 3.0 (2006):

zig-zag
    adj 1: having short sharp turns or angles [syn: zigzag, zig-
           zag]

Moby Thesaurus II by Grady Ward, 1.0:

212 Moby Thesaurus words for "zigzag":
   L, V-shaped, Y-shaped, aberrancy, aberrant, aberration, aberrative,
   akimbo, alternate, angle, angle off, angular, apex, avoidance,
   avoiding reaction, back and fill, battledore and shuttlecock, bend,
   bendy, bent, bias, bifurcate, bifurcation, bight, branch,
   branching off, cant, chevron, chevronwise, chevrony, circuitous,
   circuitousness, circumvention, coin, come and go, corner, cornered,
   crank, crankiness, crankle, crankled, crook, crooked, crookedness,
   crotched, crotchet, curve, curvy, declination, defense mechanism,
   deflect, deflection, departing, departure, desultory, detour,
   deviance, deviancy, deviant, deviate, deviating, deviation,
   deviative, deviatory, devious, deviousness, diffract, diffuse,
   digression, digressive, discursion, discursive, disperse, distort,
   divagation, divarication, diverge, divergence, diversion, divert,
   dodge, dogleg, double, drift, drifting, duck, ebb and flow, elbow,
   ell, elusion, elusiveness, equivocation, errant, errantry, erratic,
   escape, evasion, evasive action, evasiveness, excursion, excursive,
   excursus, exorbitation, flexuosity, flexuous, forbearance,
   forestalling, forestallment, fork, forked, furcal, furcate,
   furcation, geniculate, geniculated, getting around, hairpin,
   hitch and hike, hook, hooked, indirect, indirection, inflection,
   jagged, jink, knee, knee-shaped, labyrinthine, mazy, meandering,
   neutrality, nonintervention, noninvolvement, nook, obliquity,
   out-of-the-way, pass and repass, pererration, planetary, point,
   pointed, prevention, pull, quoin, rambling, reciprocate, refract,
   refraining, ride and tie, roving, saw-toothed, sawtooth, scatter,
   seesaw, serpentine, serrate, sharp, sharp-cornered, sheer, shift,
   shifting, shifting course, shifting path, shunning, shunting off,
   shuttle, shuttlecock, shy, sidestep, sidetracking, skew, slant,
   slip, snaky, stagger, staggered, stray, straying, sweep, swerve,
   swerving, swing, swinging, switchback, tack, teeter, teeter-totter,
   the runaround, to-and-fro, turn, turning, twist, twisting, twisty,
   undirected, vagrant, variation, veer, veering, vertex, wandering,
   warp, wax and wane, wibble-wabble, wigwag, winding, yaw, zag, zig,
   zigzaggery, zigzaggy, zigzagways



The Devil's Dictionary (1881-1906):

ZIGZAG, v.t.  To move forward uncertainly, from side to side, as one
carrying the white man's burden.  (From _zed_, _z_, and _jag_, an
Icelandic word of unknown meaning.)

    He zedjagged so uncomen wyde
    Thet non coude pas on eyder syde;
    So, to com saufly thruh, I been
    Constreynet for to doodge betwene.
                                                               Munwele