Poor holding on for money (5)
I believe the answer is:
bread
'money' is the definition.
(bread is slang for money)
'poor holding on' is the wordplay.
'poor' becomes 'bad' (similar in meaning).
'holding' means one lot of letters goes inside another.
'on' becomes 're' ('on' can be mean 'with reference to').
'bad' placed around 're' is 'BREAD'.
'for' is the link.
(Other definitions for bread that I've seen before include "Dosh - a bloomer, perhaps?" , "Food made from dough" , "Staple diet" , "Eg, loaf or rolls" , "Bloomers, say" .)