narcissus vs jonquil

narcissus and jonquil both are nouns.

Word	Noun	Adjective	Verb	Adverb
narcissus	Yes	No	No	No
jonquil	Yes	No	No	No

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

narcissus: bulbous plant having erect linear leaves and showy yellow or white flowers either solitary or in clusters
jonquil: widely cultivated ornamental plant native to southern Europe but naturalized elsewhere having fragrant yellow or white clustered flowers

Other hyponyms of narcissus include daffodil, Narcissus pseudonarcissus, Narcissus jonquilla.

narcissus (noun)	jonquil (noun)
bulbous plant having erect linear leaves and showy yellow or white flowers either solitary or in clusters	widely cultivated ornamental plant native to southern Europe but naturalized elsewhere having fragrant yellow or white clustered flowers
	often used colloquially for any yellow daffodil