hard hat vs journeyman

hard hat and journeyman both are nouns.

Word	Noun	Adjective	Verb	Adverb
hard hat	Yes	No	No	No
journeyman	Yes	No	No	No

As nouns, journeyman is a hypernym of hard hat; that is, journeyman is a word with a broader meaning than hard hat:

Other hypernyms of hard hat include artificer, artisan, craftsman.

hard hat (noun)	journeyman (noun)
a lightweight protective helmet (plastic or metal) worn by construction workers	a skilled worker who practices some trade or handicraft
a worker skilled in building offices or dwellings etc.