fan vs metalhead

fan and metalhead both are nouns.

Word	Noun	Adjective	Verb	Adverb
fan	Yes	No	Yes	No
metalhead	Yes	No	No	No

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

fan (noun)	metalhead (noun)
a device for creating a current of air by movement of a surface or surfaces	a fan of heavy metal music
an ardent follower and admirer
an enthusiastic devotee of sports

fan (verb)	metalhead (verb)
make (an emotion) fiercer
blow away or off with a current of air
strike out (a batter), (of a pitcher)
agitate the air