sow thistle vs shrub

sow thistle and shrub both are nouns.

Word	Noun	Adjective	Verb	Adverb
sow thistle	Yes	No	No	No
shrub	Yes	No	No	No

As nouns, shrub is a hypernym of sow thistle; that is, shrub is a word with a broader meaning than sow thistle:

sow thistle: any of several Old World coarse prickly-leaved shrubs and subshrubs having milky juice and yellow flowers; widely naturalized; often noxious weeds in cultivated soil
shrub: a low woody perennial plant usually having several major stems

Other hypernyms of sow thistle include bush.

sow thistle (noun)	shrub (noun)
any of several Old World coarse prickly-leaved shrubs and subshrubs having milky juice and yellow flowers; widely naturalized; often noxious weeds in cultivated soil	a low woody perennial plant usually having several major stems