Will producer examine a rocky hill? (8)
I believe the answer is:
testator
'will producer' is the definition.
(someone who produces wills)
'examine a rocky hill?' is the wordplay.
'examine' becomes 'test' (synonyms).
'rocky hill?' becomes 'tor' (I've seen this before).
'test'+'a'+'tor'='TESTATOR'
(Other definitions for testator that I've seen before include "Male maker of will" , "Will producer" , "Will compiler" , "A man who has made a will" , "Person making a will" .)