field mustard vs charlock

field mustard and charlock both are nouns.

Word	Noun	Adjective	Verb	Adverb
field mustard	Yes	No	No	No
charlock	Yes	No	No	No

As nouns, field mustard and charlock are synonyms defined as:

field mustard and charlock: weedy Eurasian plant often a pest in grain fields

Other synonyms of field mustard include Brassica kaber, chadlock, Sinapis arvensis, wild mustard.

field mustard (noun)	charlock (noun)
weedy Eurasian plant often a pest in grain fields	weedy Eurasian plant often a pest in grain fields