desire vs arousal

desire and arousal both are nouns.

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

As nouns, arousal is a hypernym of desire; that is, arousal is a word with a broader meaning than desire:

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

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