loud vs fortissimo

loud is not a noun while fortissimo is a noun.

Word	Noun	Adjective	Verb	Adverb
loud	No	Yes	No	Yes
fortissimo	Yes	Yes	No	Yes

loud (noun)	fortissimo (noun)
	a musical composition or musical passage to be performed very loudly

loud (adjective)	fortissimo (adjective)
characterized by or producing sound of great volume or intensity	(chiefly a direction or description in music) very loud and strong
(used chiefly as a direction or description in music) indicating that said piece or segment should be played loudly
tastelessly showy

loud (adverb)	fortissimo (adverb)
with relatively high volume	a direction in music; to be played very loudly