Phosphorus vs morning star

Phosphorus and morning star both are nouns.

Word	Noun	Adjective	Verb	Adverb
Phosphorus	Yes	No	No	No
morning star	Yes	No	No	No

As nouns, Phosphorus and morning star are synonyms defined as:

Phosphorus and morning star: a planet (usually Venus) seen just before sunrise in the eastern sky

Other synonyms of Phosphorus include daystar, Lucifer.

Phosphorus (noun)	morning star (noun)
a planet (usually Venus) seen just before sunrise in the eastern sky	a planet (usually Venus) seen just before sunrise in the eastern sky