plant bug vs leaf bug

plant bug and leaf bug both are nouns.

Word	Noun	Adjective	Verb	Adverb
plant bug	Yes	No	No	No
leaf bug	Yes	No	No	No

As nouns, plant bug and leaf bug are synonyms defined as:

plant bug and leaf bug: small bright-colored insect that feeds on plant juices

plant bug (noun)	leaf bug (noun)
small bright-colored insect that feeds on plant juices	small bright-colored insect that feeds on plant juices