Synonyms for Bumble (same or very similar meaning)
WordNet sense 1 (make a mess of, destroy or ruin):
blow, bobble, bollix, botch, bungle, flub, fluff, fumble, mishandle, spoil, screw up, bodge, bollix up, bollocks up, botch up, louse up, muck upWordNet sense 2 (walk unsteadily):
falter, stumbleWordNet sense 3 (speak haltingly):
stammer, stutterFrom the ODE community, based on WordNetadd/edit