builder vs housebuilder

builder and housebuilder both are nouns.

Word	Noun	Adjective	Verb	Adverb
builder	Yes	No	No	No
housebuilder	Yes	No	No	No

As nouns, housebuilder is a hyponym of builder; that is, housebuilder is a word with a more specific, narrower meaning than builder:

builder: someone who contracts for and supervises construction (as of a building)
housebuilder: someone who builds houses as a business

builder (noun)	housebuilder (noun)
someone who contracts for and supervises construction (as of a building)	someone who builds houses as a business
a person who creates a business or who organizes and develops a country
a substance added to soaps or detergents to increase their cleansing action