Source : Webster's Revised Unabridged Dictionary (1913)

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

Source : WordNet®

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