quick grass vs quack grass

quick grass and quack grass both are nouns.

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

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

quick grass and quack 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, dog grass, quackgrass, witch grass, witchgrass.

quick 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