Real Dictionary

unwieldy
adjective: If you describe a system as unwieldy, you mean that it does not work very well as a result of it being too large or badly organized.
adjective: If you describe an object as unwieldy, you mean that it is difficult to move or carry because it is so big or heavy.

unwieldy in American English
hard to wield, manage, handle, or deal with, as because of large size or weight, or awkward form
adjective: not wieldy; wielded with difficulty; not readily handled or managed in use or action, as from size, shape, or weight; awkward; ungainly

unwieldy in British English
adjective: too heavy, large, or awkwardly shaped to be easily handled