quackgrass vs witch grass

quackgrass and witch grass both are nouns.

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

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

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

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

quackgrass (noun)	witch grass (noun)
European grass spreading rapidly by creeping rhizomes; naturalized in North America as a weed	North American grass with slender brushy panicles; often a weed on cultivated land
	European grass spreading rapidly by creeping rhizomes; naturalized in North America as a weed