telegraph operator vs telegraphist

telegraph operator and telegraphist both are nouns.

Word	Noun	Adjective	Verb	Adverb
telegraph operator	Yes	No	No	No
telegraphist	Yes	No	No	No

As nouns, telegraph operator and telegraphist are synonyms defined as:

telegraph operator and telegraphist: someone who transmits messages by telegraph

Other synonyms of telegraph operator include telegrapher.

telegraph operator (noun)	telegraphist (noun)
someone who transmits messages by telegraph	someone who transmits messages by telegraph