The Collaborative International Dictionary of English v.0.48:

Mosey \Mo"sey\, v. i. [Perh. fr. Vamose.]
   To go, or move (in a certain manner); -- usually with out,
   off, along, etc. [Colloq.] --E. N. Wescott.
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

mosey
    v 1: walk leisurely [syn: amble, mosey]