coffee vs coffee tree

coffee and coffee tree both are nouns.

Word	Noun	Adjective	Verb	Adverb
coffee	Yes	No	No	No
coffee tree	Yes	No	No	No

As nouns, coffee and coffee tree are synonyms defined as:

coffee and coffee tree: any of several small trees and shrubs native to the tropical Old World yielding coffee beans

coffee (noun)	coffee tree (noun)
a medium brown to dark-brown color	any of several small trees and shrubs native to the tropical Old World yielding coffee beans
a beverage consisting of an infusion of ground coffee beans
a seed of the coffee tree; ground to make coffee
any of several small trees and shrubs native to the tropical Old World yielding coffee beans