Leave some food and water (8)
I believe the answer is:
farewell
'leave' is the definition.
(I know that leave can be written as farewell)
'some food and water' is the wordplay.
'some food' becomes 'fare' (fare is a kind of food).
'and' says to put letters next to each other.
'water' becomes 'well' (well water is a kind of water).
'fare'+'well'='FAREWELL'
(Other definitions for farewell that I've seen before include "Archaic goodbye - good luck" , "Departure" , "All the best" , "Cape at the southernmost point of Greenland" , "symphony" .)