taxi vs taxicab

taxi and taxicab both are nouns.

Word	Noun	Adjective	Verb	Adverb
taxi	Yes	No	Yes	No
taxicab	Yes	No	No	No

As nouns, taxi and taxicab are synonyms defined as:

taxi and taxicab: a car driven by a person whose job is to take passengers where they want to go in exchange for money

Other synonyms of taxi include cab, hack.

taxi (noun)	taxicab (noun)
a car driven by a person whose job is to take passengers where they want to go in exchange for money	a car driven by a person whose job is to take passengers where they want to go in exchange for money

taxi (verb)	taxicab (verb)
ride in a taxicab
travel slowly