penny grass vs fanweed

penny grass and fanweed both are nouns.

Word	Noun	Adjective	Verb	Adverb
penny grass	Yes	No	No	No
fanweed	Yes	No	No	No

As nouns, penny grass and fanweed are synonyms defined as:

penny grass and fanweed: foetid Eurasian weed having round flat pods; naturalized throughout North America

Other synonyms of penny grass include field pennycress, French weed, mithridate mustard, stinkweed, Thlaspi arvense.

penny grass (noun)	fanweed (noun)
foetid Eurasian weed having round flat pods; naturalized throughout North America	foetid Eurasian weed having round flat pods; naturalized throughout North America