gnu vs antelope

gnu and antelope both are nouns.

Word	Noun	Adjective	Verb	Adverb
gnu	Yes	No	No	No
antelope	Yes	No	No	No

As nouns, antelope is a hypernym of gnu; that is, antelope is a word with a broader meaning than gnu:

gnu: large African antelope having a head with horns like an ox and a long tufted tail
antelope: graceful Old World ruminant with long legs and horns directed upward and backward; includes gazelles, springboks, impalas, addax, gerenuks, blackbucks, dik-diks

gnu (noun)	antelope (noun)
large African antelope having a head with horns like an ox and a long tufted tail	graceful Old World ruminant with long legs and horns directed upward and backward; includes gazelles, springboks, impalas, addax, gerenuks, blackbucks, dik-diks