A noisy, old pick-up truck lumbered past us.
The verb lumber in the above sentence is suggestive of the slow and heavy movement of the truck. You could say that bears lumber , to suggest their awkward gait. And the elephant lumbering up the muddy hill also suggests the heavy awkward movement. And sometimes when you walk in a clumsy and ungraceful manner you are lumbering too!
I know, that’s not so funny!
The word lumber when used as a noun means wood that has been cut into various lengths for different building purposes. It means the same as timber.
A lumberjack is a person who cuts down trees. And, if you are lumbered with something, then it means you are burdened with something. For eg: She did not want to be lumbered with the job of cleaning up after the party. A lot to do with the word lumber !