law vs undue

law is a noun but undue is not a noun.

Word	Noun	Adjective	Verb	Adverb
law	Yes	No	No	No
undue	No	Yes	No	No

law (noun)	undue (noun)
the learned profession that is mastered by graduate study in a law school and that is responsible for the judicial system
a rule or body of rules of conduct inherent in human nature and essential to or binding upon human society
a generalization that describes recurring facts or events in nature
the branch of philosophy concerned with the law and the principles that lead courts to make the decisions they do
legal document setting forth rules governing a particular kind of activity
the collection of rules imposed by authority
the force of policemen and officers

law (adjective)	undue (adjective)
	not yet payable
	not appropriate or proper (or even legal) in the circumstances
	beyond normal limits
	lacking justification or authorization