star apple vs fruit tree

star apple and fruit tree both are nouns.

Word	Noun	Adjective	Verb	Adverb
star apple	Yes	No	No	No
fruit tree	Yes	No	No	No

As nouns, fruit tree is a hypernym of star apple; that is, fruit tree is a word with a broader meaning than star apple:

star apple: evergreen tree of West Indies and Central America having edible purple fruit star-shaped in cross section and dark green leaves with golden silky undersides
fruit tree: tree bearing edible fruit

star apple (noun)	fruit tree (noun)
evergreen tree of West Indies and Central America having edible purple fruit star-shaped in cross section and dark green leaves with golden silky undersides	tree bearing edible fruit