headgear vs wearable

headgear and wearable both are nouns.

Word	Noun	Adjective	Verb	Adverb
headgear	Yes	No	No	No
wearable	Yes	Yes	No	No

As nouns, wearable is a hypernym of headgear; that is, wearable is a word with a broader meaning than headgear:

Other hypernyms of headgear include article of clothing, clothing, habiliment, vesture, wear.

headgear (noun)	wearable (noun)
clothing for the head	a covering designed to be worn on a person's body
stable gear consisting of any part of a harness that fits about the horse's head
the hoist at the pithead of a mine

headgear (adjective)	wearable (adjective)
	suitable for wear or able to be worn