One cutting ration admitting the end of futile resistance (7)
I believe the answer is:
shearer
'one cutting' is the definition.
(someone shearing things)
'ration admitting the end of futile resistance' is the wordplay.
'ration' becomes 'share' (a ration is a share of a limited resource).
'admitting' is an insertion indicator (admit can mean to welcome in or accept).
'the end of' indicates one should take the final letters.
'resistance' becomes 'r' (electronics abbreviation).
The last letter of 'futile' is 'e'.
'share' enclosing 'e' is 'sheare'.
'sheare'+'r'='SHEARER'
(Other definitions for shearer that I've seen before include "One that's fleeced" , "Sheep barber?" , "one who removes coat" , "Alan - - , Newcastle striker" , "He cuts the fleece from sheep" .)