Painting of gorilla oddly missing (3)
I believe the answer is:
oil
'painting' is the definition.
(oil painting is a kind of painting)
'gorilla oddly missing' is the wordplay.
'oddly missing' indicates alternate letters (letters in odd-numbered positions removed).
The alternate letters of 'gorilla' are 'OIL'.
'of' acts as a link.
(Other definitions for oil that I've seen before include "Lubricate; fuel" , "Liquid fuel" , "Type of fuel" , "Lubricating liquid" , "Valuable viscous liquid" .)