Pass old lover on island (7)
I believe the answer is:
excrete
'pass' is the definition.
('excrete' can be a synonym of 'pass')
'old lover on island' is the wordplay.
'old lover' becomes 'ex' (I've seen this in other clues).
'on' says to put letters next to each other.
'island' becomes 'crete' (Crete is an example**).
'ex'+'crete'='EXCRETE'
(Other definitions for excrete that I've seen before include "Expel (waste) from the body" , "Defecate" , "Eliminate (from the body)" .)