hemp vs Cannabis indica

hemp and Cannabis indica both are nouns.

Word	Noun	Adjective	Verb	Adverb
hemp	Yes	No	No	No
Cannabis indica	Yes	No	No	No

As nouns, Cannabis indica is a hyponym of hemp; that is, Cannabis indica is a word with a more specific, narrower meaning than hemp:

hemp: any plant of the genus Cannabis; a coarse bushy annual with palmate leaves and clusters of small green flowers; yields tough fibers and narcotic drugs
Cannabis indica: source of e.g. bhang and hashish as well as fiber

Other hyponyms of hemp include Cannabis sativa, ganja, marihuana, marijuana, Indian hemp.

hemp (noun)	Cannabis indica (noun)
a rope that is used by a hangman to execute persons who have been condemned to death by hanging	source of e.g. bhang and hashish as well as fiber
any plant of the genus Cannabis; a coarse bushy annual with palmate leaves and clusters of small green flowers; yields tough fibers and narcotic drugs
a plant fiber