demur vs demurrer

demur and demurrer both are nouns.

Word	Noun	Adjective	Verb	Adverb
demur	Yes	No	Yes	No
demurrer	Yes	No	No	No

As nouns, demur and demurrer are synonyms defined as:

Other synonyms of demur include demurral.

demur (noun)	demurrer (noun)
(law) a formal objection to an opponent's pleadings	a defendant's answer or plea denying the truth of the charges against him
	(law) a formal objection to an opponent's pleadings
	(law) any pleading that attacks the legal sufficiency of the opponent's pleadings

demur (verb)	demurrer (verb)
object to
enter a demurrer