dog grass vs quack grass

dog grass and quack grass both are nouns.

Word	Noun	Adjective	Verb	Adverb
dog grass	Yes	No	No	No
quack grass	Yes	No	No	No

As nouns, dog grass and quack grass are synonyms defined as:

dog grass and quack grass: European grass spreading rapidly by creeping rhizomes; naturalized in North America as a weed

Other synonyms of dog grass include Agropyron repens, couch grass, quackgrass, quick grass, witch grass, witchgrass.

dog grass (noun)	quack grass (noun)
European grass spreading rapidly by creeping rhizomes; naturalized in North America as a weed	European grass spreading rapidly by creeping rhizomes; naturalized in North America as a weed