wild plum vs hog plum

wild plum and hog plum both are nouns.

Word	Noun	Adjective	Verb	Adverb
wild plum	Yes	No	No	No
hog plum	Yes	No	No	No

As nouns, wild plum and hog plum are synonyms defined as:

wild plum and hog plum: fruit of the wild plum of southern United States

As nouns, hog plum is a hyponym of wild plum; that is, hog plum is a word with a more specific, narrower meaning than wild plum:

wild plum: an uncultivated plum tree or shrub
hog plum: small native American shrubby tree bearing small edible yellow to reddish fruit

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