Salesperson in ground cited as feeble (8)
I believe the answer is:
decrepit
'feeble' is the definition.
(I know that feeble can be written as decrepit)
'salesperson in ground cited' is the wordplay.
'salesperson' becomes 'rep' (sales rep).
'in' is an insertion indicator.
'ground' indicates an anagram ('grind' the letters into a new form).
'cited' is an anagram of 'decit'.
'rep' inserted into 'decit' is 'DECREPIT'.
'as' acts as a link.
(Other definitions for decrepit that I've seen before include "Depicter in state of dilapidation" , "Pet cried (anag) - worn out" , "Worn-out" , "Elderly, infirm" , "past its best" .)