Bumble :: Bumble (v. i.) To make a hollow or humming noise, like that of a bumblebee; to cry as a bittern..
Bumblebee :: Bumblebee (n.) A large bee of the genus Bombus, sometimes called humblebee; -- so named from its sound..
Crumble :: Crumble (v. t.) To break into small pieces; to cause to fall in pieces.
Crumble :: Crumble (v. i.) To fall into small pieces; to break or part into small fragments; hence, to fall to decay or ruin; to become disintegrated; to perish..