quick grass vs quackgrass

quick grass and quackgrass both are nouns.

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

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

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

quick grass (noun)	quackgrass (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