Beg for a pad to put round a leg that's not good (5)
I believe the answer is:
plead
'beg' is the definition.
(I've seen this before)
'a pad to put round a leg that's not good' is the wordplay.
'to put round' is an insertion indicator.
'that's not' suggests deleting specific letters.
'good' becomes 'g' (abbreviation).
'leg' with 'g' taken away is 'le'.
'pad' going around 'le' is 'PLEAD'.
'for' is the link.
(Other definitions for plead that I've seen before include "Respond to charge" , "Beg, implore" , "Appeal humbly (to)" , "Present an argument in court" , "Argue (for a cause)" .)