cabby vs livery driver

cabby and livery driver both are nouns.

Word	Noun	Adjective	Verb	Adverb
cabby	Yes	No	No	No
livery driver	Yes	No	No	No

As nouns, cabby and livery driver are synonyms defined as:

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

cabby (noun)	livery driver (noun)
someone who drives a taxi for a living	someone who drives a taxi for a living