Bunk (10)
'bunk' is the definition.
(I know that balderdash is a type of bunk)
This is all the clue.
(Other definitions for balderdash that I've seen before include "Nonsense" , "garbage" , "Rubbish" , "Bunk" , "Poppycock" .)
(Other definitions for beds that I've seen before include "to which people may retire" , "County; furniture" , "Garden plots - English county (abbr)" , "Hospital places" , "Cots, bunks etc -- eastern English county (abbr)" .)