tiger vs tiger cub

tiger and tiger cub both are nouns.

Word	Noun	Adjective	Verb	Adverb
tiger	Yes	No	No	No
tiger cub	Yes	No	No	No

As nouns, tiger cub is a hyponym of tiger; that is, tiger cub is a word with a more specific, narrower meaning than tiger:

tiger: large feline of forests in most of Asia having a tawny coat with black stripes; endangered
tiger cub: a young tiger

Other hyponyms of tiger include Bengal tiger, tigress.

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