rockcress vs weed

rockcress and weed both are nouns.

Word	Noun	Adjective	Verb	Adverb
rockcress	Yes	No	No	No
weed	Yes	No	Yes	No

As nouns, weed is a hypernym of rockcress; that is, weed is a word with a broader meaning than rockcress:

rockcress: noxious cress with yellow flowers; sometimes placed in genus Sisymbrium
weed: any plant that crowds out cultivated plants

rockcress (noun)	weed (noun)
any of several rock-loving cresses of the genus Arabis	street names for marijuana
noxious cress with yellow flowers; sometimes placed in genus Sisymbrium	a black band worn by a man (on the arm or hat) as a sign of mourning
	any plant that crowds out cultivated plants

rockcress (verb)	weed (verb)
	clear of weeds