Half the local food is not tough or oily (6)
I believe the answer is:
greasy
'oily' is the definition.
('greasy' can be a synonym of 'oily')
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for greasy that I've seen before include "Like the pole that is hard to climb" , "Cheap 24" , "Oily or smeared with fat" , "Sticky with fat" , "Thickly oleaginous" .)