I always associate lumbering with large ungainly animals like rhinos or hippos. As they lumber toward you they kick up clouds of dust and the ground shakes beneath your feet. Lumbering animals might seem clumsy, but I have always thought of them as very determined and their straight line destination inevitable.
Smaller animals might be said to trundle along, equally ungainly but not so substantial and fearsome as those beasts that lumber. Raccoons and hedgehogs trundle as they careen along in their clever ways, operating just below our sight lines, little tricksters that they are. Some objects like a suitcase trundle by rolling along on their little wheels, in fact the noun form of trundle is wheel.
If it’s nice outside we can take the long way round and go for an amble. There we are bopping along with seemingly not a care in the world. Nothing on the schedule today, perfect time for an amble. Amble comes from the latin word ambulare, meaning to walk about.
Add an “sh” and we become zombies lurching along in a shambling walk. Unless we are those real scary zombies that can run real fast, a situation which is totally unfair and breaks all the laws of zombie physics.
I can imagine Yeats wrestling with all these forms of motility before finally arriving at;
“And what rough beast, its hour come round at last,
Slouches towards Bethlehem to be born?”
“Ambling” towards Bethlehem just doesn’t carry the same sense of dread as slouching, does it?