hog plum vs fruit tree

hog plum and fruit tree both are nouns.

Word	Noun	Adjective	Verb	Adverb
hog plum	Yes	No	No	No
fruit tree	Yes	No	No	No

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

hog plum (noun)	fruit tree (noun)
fruit of the wild plum of southern United States	tree bearing edible fruit
yellow oval tropical fruit
small native American shrubby tree bearing small edible yellow to reddish fruit
tropical American tree having edible yellow fruit