The Collaborative International Dictionary of English v.0.48:

Wieldy \Wield"y\, a.
   Capable of being wielded; manageable; wieldable; -- opposed
   to unwieldy. [R.] --Johnson.
   [1913 Webster]

WordNet (r) 3.0 (2006):

wieldy
    adj 1: easy to handle or use or manage; "a large but wieldy
           book" [ant: unmanageable, unwieldy]

Moby Thesaurus II by Grady Ward, 1.0:

19 Moby Thesaurus words for "wieldy":
   adaptable, convenient, ductile, feasible, flexible, foolproof,
   handy, malleable, manageable, maneuverable, mighty, pliable,
   pliant, powerful, practical, tractable, untroublesome, wieldable,
   yielding