hard hat vs construction worker

hard hat and construction worker both are nouns.

Word	Noun	Adjective	Verb	Adverb
hard hat	Yes	No	No	No
construction worker	Yes	No	No	No

As nouns, hard hat and construction worker are synonyms defined as:

hard hat and construction worker: a worker skilled in building offices or dwellings etc.

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