An unwieldy object is difficult to move or handle because it is heavy, large, or a strange shape.

中文解释

（物体因沉重、庞大或形状奇特而）不灵便的，笨重的；难移动的 A piano is a very unwieldy item to get down a flight of stairs. 钢琴是个很难搬下楼梯的物件。