Fed back, I see it as a shortage (7)
I believe the answer is:
deficit
'a shortage' is the definition.
(synonyms)
'fed back i see it' is the wordplay.
'back' shows that the letters should be reversed in order.
'see' becomes 'C' (the word for the letter, according to Chambers).
'fed' reversed gives 'def'.
'def'+'i'+'c'+'it'='DEFICIT'
'as' is the link.
(Other definitions for deficit that I've seen before include "Excess of expenditure over income" , "Shortage" , "Want" , "There's something lacking" , "Arrears" .)