lumbering adjective 2noun 2forms 3 adjective2 •Clumsy or awkward.I've kidnapped that lumbering fool Donkey Kong and you will never see him again. Har-har-har-har! — 1995 •Heavy, slow and laborious; ponderous. noun2 •(US) The business of felling trees for lumber. •The act of one who lumbers; heavy, clumsy movement.Only the old harbor-master was there, singing out, as by duty bound, his lusty oaths at their lumberings. — 1887 formslumberings · more lumbering · most lumbering