WordNet sense 1 (difficult to handle or manage especially because of shape):

awkward, clumsy, ungainly

WordNet sense 2 (difficult to use or handle or manage because of size or weight or shape):

unwieldy

WordNet sense 3 (of persons):

uncontrollable, ungovernable, unruly, indocile

WordNet sense 4 (difficult to manage or control):

difficult

WordNet sense 5 (incapable of being controlled or managed):

uncorrectable

WordNet sense 6 (impervious to correction by punishment):

incorrigible