water bug vs crotonbug

water bug and crotonbug both are nouns.

Word	Noun	Adjective	Verb	Adverb
water bug	Yes	No	No	No
crotonbug	Yes	No	No	No

As nouns, water bug and crotonbug are synonyms defined as:

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

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

water bug (noun)	crotonbug (noun)
a true bug: large aquatic bug adapted to living in or on the surface of water	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