quick grass vs dog grass

quick grass and dog grass both are nouns.

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

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

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

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

quick grass (noun)	dog 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