The Collaborative International Dictionary of English v.0.48:

Limber \Lim"ber\ v. t. [imp. & p. p. Limbered
   (l[i^]m"b[~e]rd); p. pr. & vb. n. Limbering.] (Mil.)
   To attach to the limber; as, to limber a gun.
   [1913 Webster]

   To limber up, to change a gun carriage into a four-wheeled
      vehicle by attaching the limber.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Limber \Lim"ber\, a. [Akin to limp, a. [root]125. See Limp,
   a.]
   Easily bent; flexible; pliant; yielding. --Milton.
   [1913 Webster]

         The bargeman that doth row with long and limber oar.
                                                  --Turbervile.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Limber \Lim"ber\ (l[i^]m"b[~e]r), n. [For limmer, Icel. limar
   branches, boughs, pl. of lim; akin to E. limb. See Limb a
   branch.]
   1. pl. The shafts or thills of a wagon or carriage. [Prov.
      Eng.]
      [1913 Webster]

   2. (Mil.) The detachable fore part of a gun carriage,
      consisting of two wheels, an axle, and a shaft to which
      the horses are attached. On top is an ammunition box upon
      which the cannoneers sit.
      [1913 Webster]

   3. pl. (Naut.) Gutters or conduits on each side of the
      keelson to afford a passage for water to the pump well.
      [1913 Webster]

   Limber boards (Naut.), short pieces of plank forming part
      of the lining of a ship's floor immediately above the
      timbers, so as to prevent the limbers from becoming
      clogged.

   Limber box or Limber chest (Mil.), a box on the limber
      for carrying ammunition.

   Limber rope, Limber chain or Limber clearer (Naut.), a
      rope or chain passing through the limbers of a ship, by
      which they may be cleared of dirt that chokes them.
      --Totten.

   Limber strake (Shipbuilding), the first course of inside
      planking next the keelson.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Limber \Lim"ber\, v. t.
   To cause to become limber; to make flexible or pliant.
   --Richardson.
   [1913 Webster]

WordNet (r) 3.0 (2006):

limber
    adj 1: (used of e.g. personality traits) readily adaptable; "a
           supple mind"; "a limber imagination" [syn: limber,
           supple]
    2: (used of artifacts) easily bent
    3: (used of persons' bodies) capable of moving or bending freely
       [syn: limber, supple]
    n 1: a two-wheeled horse-drawn vehicle used to pull a field gun
         or caisson
    v 1: attach the limber; "limber a cannon" [syn: limber,
         limber up]
    2: cause to become limber; "The violist limbered her wrists
       before the concert"

Moby Thesaurus II by Grady Ward, 1.0:

86 Moby Thesaurus words for "limber":
   adaptable, anemic, asthenic, bendable, bending, bloodless, chicken,
   compliant, cowardly, debilitated, drooping, droopy, ductile, dull,
   effete, elastic, etiolated, extensible, extensile, fabricable,
   facile, faint, faintish, feeble, fictile, flabby, flaccid,
   flexible, flexile, flexuous, floppy, formable, formative, giving,
   gone, gutless, imbecile, impotent, impressible, impressionable,
   languid, languorous, like putty, limp, lissome, listless, lithe,
   lithesome, lustless, malleable, marrowless, moldable, nerveless,
   pithless, plastic, pliable, pliant, pooped, powerless, receptive,
   resilient, responsive, rubbery, sapless, sensitive, sequacious,
   shapable, sinewless, slack, soft, spineless, springy, strengthless,
   submissive, supple, susceptible, tractable, tractile, unhardened,
   unnerved, unstrung, weak, weakly, whippy, willowy, yielding