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):

truckling
    n 1: the act of obeying meanly (especially obeying in a humble
         manner or for unworthy reasons)

Moby Thesaurus II by Grady Ward, 1.0:

44 Moby Thesaurus words for "truckling":
   abject, apple-polishing, ass-kissing, backscratching, beggarly,
   bootlicking, brown-nosing, cowering, crawling, cringing, crouching,
   fawnery, fawning, flattering, flunkyism, footlicking, groveling,
   handshaking, hangdog, ingratiating, ingratiation, insinuation,
   kowtowing, mealymouthed, mealymouthedness, obeisance, obeisant,
   obsequious, obsequiousness, on bended knee, parasitic, parasitism,
   prostrate, prostration, sniveling, sponging, sycophancy,
   sycophantic, timeserving, toadeating, toadying, toadyish, toadyism,
   tufthunting