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1. Difficult to use or handle or manage because of size or weight or shape
   "we set about towing the unmanageable structure into the shelter"
   - unwieldy
    
2. Hard to control
   "an unmanageable situation"
   - difficult
    
3. Difficult to solve or alleviate
   "unmanageable pain"
   - uncontrollable
    
4. Incapable of being controlled or managed
   "unmanageable children"
   - uncontrollable, uncorrectable

See also: awkward, bunglesome, clumsy, cumbersome, cumbrous, defiant, disobedient, incorrigible, indocile, intractable, noncompliant, uncheckable, uncontrollable, ungainly, ungovernable, unmanageableness, unmanageably, unruly

Antonym: manageable