arousal vs kissing

arousal and kissing both are nouns.

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

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

arousal: mutual sexual fondling prior to sexual intercourse
kissing: affectionate play (or foreplay without contact with the genital organs)

Other hyponyms of arousal include caressing, cuddling, fondling, hugging, necking, petting, smooching, snuggling, feel.

arousal (noun)	kissing (noun)
the act of arousing	affectionate play (or foreplay without contact with the genital organs)
mutual sexual fondling prior to sexual intercourse
awakening from sleep
a state of heightened physiological activity