quick grass vs witchgrass

quick grass and witchgrass both are nouns.

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

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

quick grass and witchgrass: 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, quackgrass, witch grass.

quick grass (noun)	witchgrass (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