truck·le 
(trŭkəl)
(trŭkəl)n.
A small wheel or roller; a caster.
intr.v. truck·led, truck·ling, truck·les
To be servile or submissive. See Synonyms at fawn1.
[Middle English trocle, pulley, from Anglo-Norman, from Latin trochlea, system of pulleys; see TROCHLEA.]
truckler n.