impala vs antelope

impala and antelope both are nouns.

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

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

impala: African antelope with ridged curved horns; moves with enormous leaps
antelope: graceful Old World ruminant with long legs and horns directed upward and backward; includes gazelles, springboks, impalas, addax, gerenuks, blackbucks, dik-diks

impala (noun)	antelope (noun)
African antelope with ridged curved horns; moves with enormous leaps	graceful Old World ruminant with long legs and horns directed upward and backward; includes gazelles, springboks, impalas, addax, gerenuks, blackbucks, dik-diks