wood vs metal wood

wood and metal wood both are nouns.

Word	Noun	Adjective	Verb	Adverb
wood	Yes	No	No	No
metal wood	Yes	No	No	No

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

wood: a golf club with a long shaft used to hit long shots; originally made with a wooden head
metal wood: golf wood with a metal head instead of the traditional wooden head

Other hyponyms of wood include brassie, driver, number one wood, spoon.

wood (noun)	metal wood (noun)
any wind instrument other than the brass instruments	golf wood with a metal head instead of the traditional wooden head
a golf club with a long shaft used to hit long shots; originally made with a wooden head
the trees and other plants in a large densely wooded area
the hard fibrous lignified substance under the bark of trees