There is at least one word that can follow BOASTING.
I will give it my BEST try,
Thats it!
BEST!
actually, plumpness is wrong, because there's an S AND a P added to lumpens... so lumpens is the final word. If you want to get picky, that is.
And my word for best is:
Beast
Plumpness is the last word. mac11 summarized incorrectly. It should be:
UMP
PLUM
PLUME
LUMPEN
PLUMPEN
PLUMPENS
PLUMPNESS
beastly