someone who emulates good ole albus dumbledore from harry potter. This can be done in numerous ways:
1) being very hairy. this does not just have to be in the beard department. it can be eyebrows, nostrils, ears or err..anywhere else.
3) a quivvering voice - very popular amongst the aging.
5) tendancy to get their wand out and flash it around a bit too much
6) walking with a hunch/eccentric stride
7) generally acting like someone who believes they own a whole magical realm yet having the assetts of an old man.
these are only a few ways to identify a dumble.
dumble-pube can also be used to describe anything wispy and grey that looks unlikely to be a dumble-beard.
'omg what a dumble!!!!!!!!!!'
'wow he is literally the most bumbling dumble i have ever seen.'
'indeed he seems to fumble more than even the most renouned dumble himself!!!'