taxidriver vs hack driver

taxidriver and hack driver both are nouns.

Word	Noun	Adjective	Verb	Adverb
taxidriver	Yes	No	No	No
hack driver	Yes	No	No	No

As nouns, taxidriver and hack driver are synonyms defined as:

Other synonyms of taxidriver include cabby, cabdriver, cabman, hack-driver, livery driver, taximan.

taxidriver (noun)	hack driver (noun)
someone who drives a taxi for a living	someone who drives a taxi for a living