Cestrum nocturnum vs shrub

Cestrum nocturnum and shrub both are nouns.

Word	Noun	Adjective	Verb	Adverb
Cestrum nocturnum	Yes	No	No	No
shrub	Yes	No	No	No

As nouns, shrub is a hypernym of Cestrum nocturnum; that is, shrub is a word with a broader meaning than Cestrum nocturnum:

Cestrum nocturnum: West Indian evergreen shrub having clusters of funnel-shaped yellow-white flowers that are fragrant by night
shrub: a low woody perennial plant usually having several major stems

Other hypernyms of Cestrum nocturnum include bush.

Cestrum nocturnum (noun)	shrub (noun)
West Indian evergreen shrub having clusters of funnel-shaped yellow-white flowers that are fragrant by night	a low woody perennial plant usually having several major stems