tanker vs tank driver

tanker and tank driver both are nouns.

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

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

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