arousal vs wakefulness

arousal and wakefulness both are nouns.

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

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

arousal: awakening from sleep
wakefulness: a periodic state during which you are conscious and aware of the world

arousal (noun)	wakefulness (noun)
the act of arousing	a periodic state during which you are conscious and aware of the world
mutual sexual fondling prior to sexual intercourse	the process of paying close and continuous attention
awakening from sleep	a temporary state in which you are unable (or unwilling) to sleep
a state of heightened physiological activity