intensity vs loudness

intensity and loudness both are nouns.

Word	Noun	Adjective	Verb	Adverb
intensity	Yes	No	No	No
loudness	Yes	No	No	No

As nouns, intensity and loudness are synonyms defined as:

intensity and loudness: the magnitude of sound (usually in a specified direction)

Other synonyms of intensity include volume.

intensity (noun)	loudness (noun)
high level or degree; the property of being intense	the magnitude of sound (usually in a specified direction)
chromatic purity: freedom from dilution with white and hence vivid in hue	tasteless showiness
the magnitude of sound (usually in a specified direction)
the amount of energy transmitted (as by acoustic or electromagnetic radiation)