backbend vs acrobatic feat

backbend and acrobatic feat both are nouns.

Word	Noun	Adjective	Verb	Adverb
backbend	Yes	No	No	No
acrobatic feat	Yes	No	No	No

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

backbend: an acrobatic feat in which the trunk is bent backward from a standing position until the hands touch the floor
acrobatic feat: a stunt performed by an acrobat

Other hypernyms of backbend include acrobatic stunt.

backbend (noun)	acrobatic feat (noun)
an acrobatic feat in which the trunk is bent backward from a standing position until the hands touch the floor	a stunt performed by an acrobat