The Collaborative International Dictionary of English v.0.48:

Truckle \Truc"kle\, n. [Dim. of truck a wheel; or from the
   kindred L. trochlea a block, sheaf containing one or more
   pulleys. See Truck a wheel.]
   A small wheel or caster. --Hudibras.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Truckle \Truc"kle\, v. i. [From truckle in truckle-bed, in
   allusion to the fact that the truckle-bed on which the pupil
   slept was rolled under the large bed of the master.]
   To yield or bend obsequiously to the will of another; to
   submit; to creep. "Small, trucking states." --Burke.
   [1913 Webster]

         Religion itself is forced to truckle to worldly poliey.
                                                  --Norris.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Truckle \Truc"kle\, v. t. [imp. & p. p. Truckled; p. pr. & vb.
   n. Truckling.]
   To roll or move upon truckles, or casters; to trundle.
   [1913 Webster]

WordNet (r) 3.0 (2006):

truckle
    n 1: a low bed to be slid under a higher bed [syn: trundle
         bed, trundle, truckle bed, truckle]
    v 1: yield to out of weakness
    2: try to gain favor by cringing or flattering; "He is always
       kowtowing to his boss" [syn: fawn, toady, truckle,
       bootlick, kowtow, kotow, suck up]

Moby Thesaurus II by Grady Ward, 1.0:

28 Moby Thesaurus words for "truckle":
   apple-polish, bootlick, bow, brown-nose, butter up, cower, crawl,
   cringe, defer, fall all over, fawn upon, follow, genuflect, grovel,
   knuckle down, knuckle under, kowtow, quail, salaam, scrape, submit,
   succumb, suck up to, tag, tail, toady, trail, yield