virulent vs acid

virulent is not a noun while acid is a noun.

Word	Noun	Adjective	Verb	Adverb
virulent	No	Yes	No	No
acid	Yes	Yes	No	No

As adjectives, virulent and acid are synonyms defined as:

Other synonyms of virulent include acerb, acerbic, acrid, bitter, blistering, caustic, sulfurous, sulphurous, vitriolic.

virulent (noun)	acid (noun)
	street name for lysergic acid diethylamide
	any of various water-soluble compounds having a sour taste and capable of turning litmus red and reacting with a base to form a salt

virulent (adjective)	acid (adjective)
infectious; having the ability to cause disease	having the characteristics of an acid
extremely poisonous or injurious; producing venom	being sour to the taste
harsh or corrosive in tone	harsh or corrosive in tone