German cockroach vs Croton bug

German cockroach and Croton bug both are nouns.

Word	Noun	Adjective	Verb	Adverb
German cockroach	Yes	No	No	No
Croton bug	Yes	No	No	No

As nouns, German cockroach and Croton bug are synonyms defined as:

German cockroach and Croton bug: small light-brown cockroach brought to United States from Europe; a common household pest

Other synonyms of German cockroach include Blattella germanica, crotonbug, water bug.

German cockroach (noun)	Croton bug (noun)
small light-brown cockroach brought to United States from Europe; a common household pest	small light-brown cockroach brought to United States from Europe; a common household pest