Operator making mother feature first (9)
I believe the answer is:
machinist
'operator' is the definition.
(I have seen 'Industrial operator ' mean 'machinist' so perhaps 'operator' could also mean 'machinist')
'mother feature first' is the wordplay.
'mother' becomes 'ma' (ma can mean mother).
'feature' becomes 'chin' (facial feature).
'first' becomes 'ist' (ist resembles 1st).
'ma'+'chin'+'ist'='MACHINIST'
'making' is the link.
(Other definitions for machinist that I've seen before include "Industrial operator" , "Engineer" , "Eg, lathe operator" , "Person operating device" , "tool operator" .)