hauler vs contractor

hauler and contractor both are nouns.

Word	Noun	Adjective	Verb	Adverb
hauler	Yes	No	No	No
contractor	Yes	No	No	No

As nouns, contractor is a hypernym of hauler; that is, contractor is a word with a broader meaning than hauler:

hauler (noun)	contractor (noun)
a haulage contractor	a bodily organ that contracts
	someone (a person or firm) who contracts to build things
	(law) a party to a contract
	the bridge player in contract bridge who wins the bidding and can declare which suit is to be trumps