tiger vs Panthera tigris

tiger and Panthera tigris both are nouns.

Word	Noun	Adjective	Verb	Adverb
tiger	Yes	No	No	No
Panthera tigris	Yes	No	No	No

As nouns, tiger and Panthera tigris are synonyms defined as:

tiger and Panthera tigris: large feline of forests in most of Asia having a tawny coat with black stripes; endangered

tiger (noun)	Panthera tigris (noun)
large feline of forests in most of Asia having a tawny coat with black stripes; endangered	large feline of forests in most of Asia having a tawny coat with black stripes; endangered
a fierce or audacious person