department head vs chief

department head and chief both are nouns.

Word	Noun	Adjective	Verb	Adverb
department head	Yes	No	No	No
chief	Yes	Yes	No	No

As nouns, chief is a hypernym of department head; that is, chief is a word with a broader meaning than department head:

Other hypernyms of department head include head, top dog.

department head (noun)	chief (noun)
the head of a department	a person who is in charge
	a person who exercises control over workers
	the head of a tribe or clan

department head (adjective)	chief (adjective)
	most important element