Stop patient eating last of cheese (5)
I believe the answer is:
cease
'stop' is the definition.
('cease' can be a synonym of 'stop')
'patient eating last of cheese' is the wordplay.
'patient' becomes 'case' ('case' can be a synonym of 'patient').
'eating' is an insertion indicator.
'last of' says to take the final letters.
The last letter of 'cheese' is 'e'.
'case' placed around 'e' is 'CEASE'.
(Other definitions for cease that I've seen before include "Stop, give over" , "Desist" , "Stop, finish" , "Stop, terminate" , "Finish, end" .)