armguard vs protective covering

armguard and protective covering both are nouns.

Word	Noun	Adjective	Verb	Adverb
armguard	Yes	No	No	No
protective covering	Yes	No	No	No

As nouns, protective covering is a hypernym of armguard; that is, protective covering is a word with a broader meaning than armguard:

armguard: a protective covering for the wrist or arm that is used in archery and fencing and other sports
protective covering: a covering that is intend to protect from damage or injury

Other hypernyms of armguard include protection, protective cover.

armguard (noun)	protective covering (noun)
a protective covering for the wrist or arm that is used in archery and fencing and other sports	the tough natural covering of some organisms
	a covering that is intend to protect from damage or injury