arousal vs desire

arousal and desire both are nouns.

Word	Noun	Adjective	Verb	Adverb
arousal	Yes	No	No	No
desire	Yes	No	Yes	No

As nouns, desire is a hyponym of arousal; that is, desire is a word with a more specific, narrower meaning than arousal:

arousal (noun)	desire (noun)
the act of arousing	an inclination to want things
mutual sexual fondling prior to sexual intercourse	the feeling that accompanies an unsatisfied state
awakening from sleep	something that is desired
a state of heightened physiological activity

arousal (verb)	desire (verb)
	feel or have a desire for; want strongly
	express a desire for
	expect and wish