Rubbish - with less hair! (10)
I believe the answer is:
balderdash
'rubbish' is the definition.
(I've seen this before)
'with less hair' is the wordplay.
I cannot quite understand how this works, but
'with less hair' could be 'balder' (I've seen this before) and 'balder' is found within the answer.
The remaining letters 'dash' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for balderdash that I've seen before include "Claptrap" , "Senseless talk/writing" , "Codswallop" , "stupid talk" , "Rubbish" .)