move heavily or clumsily
Dogs trot; bears lumber.
limber is moving swiftly. i. e to b flexible. lumber is to move heavily or awkwardly. ;) Relate to the person who is "lamba" (lamba in Hindi language means tall person in English) moves heavily or clumsily The lumberjack was lumbering with heavy lumbers on his back. Lumberjack comes in ageofempires