guava bush vs Psidium guajava

guava bush and Psidium guajava both are nouns.

Word	Noun	Adjective	Verb	Adverb
guava bush	Yes	No	No	No
Psidium guajava	Yes	No	No	No

As nouns, guava bush and Psidium guajava are synonyms defined as:

guava bush and Psidium guajava: small tropical American shrubby tree; widely cultivated in warm regions for its sweet globular yellow fruit

Other synonyms of guava bush include guava, true guava.

guava bush (noun)	Psidium guajava (noun)
small tropical American shrubby tree; widely cultivated in warm regions for its sweet globular yellow fruit	small tropical American shrubby tree; widely cultivated in warm regions for its sweet globular yellow fruit