Bread ultimately fed poorest vagrant (8)
I believe the answer is:
doorstep
'bread' is the definition.
(I've seen this before)
'ultimately fed poorest vagrant' is the wordplay.
'ultimately' suggests the final letters.
'vagrant' indicates anagramming the letters (vagrant can mean wandering around).
The last letter of 'fed' is 'd'.
'poorest' anagrammed gives 'oorstep'.
'd'+'oorstep'='DOORSTEP'
(Other definitions for doorstep that I've seen before include "Thick slice of bread (informal)" , "To conduct house-to-house interviews" , "Canvass locally" , "Try some canvassing" , "substantial amount of bread" .)