half-length vs portrayal

half-length and portrayal both are nouns.

Word	Noun	Adjective	Verb	Adverb
half-length	Yes	Yes	No	No
portrayal	Yes	No	No	No

As nouns, portrayal is a hypernym of half-length; that is, portrayal is a word with a broader meaning than half-length:

Other hypernyms of half-length include portrait.

half-length (noun)	portrayal (noun)
a portrait showing the body from only the waist up	representation by drawing or painting etc
	acting the part of a character on stage; dramatically representing the character by speech and action and gesture
	any likeness of a person, in any medium
	a representation by picture or portraiture
	a word picture of a person's appearance and character

half-length (adjective)	portrayal (adjective)
abridged to half its original length
representing only the upper half of the body