Rent unit out providing food (8)
I believe the answer is:
nutrient
'food' is the definition.
('nutrient' can be a synonym of 'food')
'rent unit out' is the wordplay.
'out' is an anagram indicator (out can mean wrong or inaccurate).
'rent'+'unit'='rentunit'
'rentunit' with letters rearranged gives 'NUTRIENT'.
'providing' is the link.
(Other definitions for nutrient that I've seen before include "Substance that nourishes" , "Substance providing nourishment" , "Substance to give energy and build tissue" , "Something providing nourishment" , "A food that keeps one alive and healthy" .)