headstand vs acrobatic stunt

headstand and acrobatic stunt both are nouns.

Word	Noun	Adjective	Verb	Adverb
headstand	Yes	No	No	No
acrobatic stunt	Yes	No	No	No

As nouns, acrobatic stunt is a hypernym of headstand; that is, acrobatic stunt is a word with a broader meaning than headstand:

headstand: an acrobatic feat in which a person balances on the head (usually with the help of the hands)
acrobatic stunt: a stunt performed by an acrobat

Other hypernyms of headstand include acrobatic feat.

headstand (noun)	acrobatic stunt (noun)
an acrobatic feat in which a person balances on the head (usually with the help of the hands)	a stunt performed by an acrobat