tank driver vs tanker

tank driver and tanker both are nouns.

Word	Noun	Adjective	Verb	Adverb
tank driver	Yes	No	No	No
tanker	Yes	No	No	No

As nouns, tank driver and tanker are synonyms defined as:

tank driver (noun)	tanker (noun)
a soldier who drives a tank	a cargo ship designed to carry crude oil in bulk
	a motor vehicle designed to carry liquefied loads, dry bulk cargo or gases on roads.
	a soldier who drives a tank