Unacceptable hoax backed by revolting drunkard runs into difficulty (3,2,2,7)
I believe the answer is:
not up to scratch
'unacceptable hoax backed' is the definition.
I know nothing about this answer so I cannot judge whether this works.
'revolting drunkard runs into difficulty' is the wordplay.
I cannot quite see how this works, but
'revolting' could be 'up' (I've seen this in other clues) and 'up' is found in the answer.
'runs' could be 'r' (cricket abbreviation) and 'r' is found within the answer.
'difficulty' could be 'catch' (I've seen this before) and 'catch' is found in the remaining letters.
This may be the basis of clue (or it may be nonsense).
'by' acts as a link.
Can you help me to learn more?
(Other definitions for not up to scratch that I've seen before include "Inadequate" , "like one bitten by bug when in bed" .)