goldbrick vs shirk

goldbrick is a noun but shirk is not a noun.

Word	Noun	Adjective	Verb	Adverb
goldbrick	Yes	No	Yes	No
shirk	No	No	Yes	No

As verbs, goldbrick and shirk are synonyms defined as:

Other synonyms of goldbrick include fiddle, shrink from.

goldbrick (noun)	shirk (noun)
anything that is supposed to be valuable but turns out to be worthless
a brick-shaped block that looks like gold but is not
an idle worthless person
a soldier who performs his duties without proper care or effort

goldbrick (verb)	shirk (verb)
avoid (one's assigned duties)	avoid dealing with
deprive of by deceit	avoid (one's assigned duties)