Painter’s forename, you’ll infer, always missing first three letters (9)

I believe the answer is:
enameller
'letters' is the definition.
Both the answer and definition are singular nouns.
Perhaps there's a link between them I don't understand?
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for enameller that I've seen before include "One decorating with glassy coatings" , "One applying vitrified coating" , "Who lacquers" , "Decorative artist" , "Craftsman" .)
