What is the relationship called between a word and something/someone that does/performs that word? [duplicate]

Basically, is there a word that relates "carpenter" to "carpentry" or "astronomer" to "astronomy"?

So if there is a subject that does some noun, is there a word or phrase for that relationship?

EDIT 1:

Sample sentence: "'activist' is a _________ of 'activism'." or "'architect' is a _________ of 'architecture'."

Solution 1:

practitioner noun [ C ] formal UK /prækˈtɪʃ.ən.ər/ US /prækˈtɪʃ.ən.ɚ/

someone involved in a skilled job or activity:

"'activist' is a practitioner of 'activism'.

"'architect' is a practitioner of 'architecture'."