telephonist vs telephone operator

telephonist and telephone operator both are nouns.

Word	Noun	Adjective	Verb	Adverb
telephonist	Yes	No	No	No
telephone operator	Yes	No	No	No

As nouns, telephonist and telephone operator are synonyms defined as:

telephonist and telephone operator: someone who helps callers get the person they are calling

Other synonyms of telephonist include switchboard operator.

telephonist (noun)	telephone operator (noun)
someone who helps callers get the person they are calling	someone who helps callers get the person they are calling