fumblechump
adj. - modifies persons, typically, who have made mistakes that exemplify stupidity. It can also be used as an expletive to denigrate another either humorously or on purpose. Other words include fumblechumpery, fumblechumpness.
Look at what he did - he's a fumblechump.
Little Johnny he broke the glass of milk - poor fumblechump.
Little Johnny he broke the glass of milk - poor fumblechump.