Small number of us on island, hard to feed (7)
I believe the answer is:
nourish
'to feed' is the definition.
(nourishing is a kind of feeding)
'small number of us on island hard' is the wordplay.
'small number' becomes 'n' (I've seen this in other clues).
'of us' becomes 'our' (I've seen this before).
'on' says to put letters next to each other.
'island' becomes 'is'.
'hard' becomes 'h'.
'n'+'our'+'is'+'h'='NOURISH'
(Other definitions for nourish that I've seen before include "Feed, sustain" , "Keep alive and well with food" , "Provide with sustenance for growth" , "Supply with food, keep well" , "Provide with food for growth" .)