pipe fitter vs plumber

pipe fitter and plumber both are nouns.

Word	Noun	Adjective	Verb	Adverb
pipe fitter	Yes	No	No	No
plumber	Yes	No	No	No

As nouns, pipe fitter and plumber are synonyms defined as:

pipe fitter and plumber: a craftsman who installs and repairs pipes and fixtures and appliances

pipe fitter (noun)	plumber (noun)
a craftsman who installs and repairs pipes and fixtures and appliances	a craftsman who installs and repairs pipes and fixtures and appliances