Past participle of the verb "smite" used adjectivally.
Definitionen
Struck, hit, or afflicted, especially by a force, disease, or calamity. The coastal town was smitten by a violent storm.
Smitten functions as an adjective meaning deeply affected or enamoured.
Definitionen
Deeply affected suddenly and strongly, especially by love, attraction, or admiration; enamoured. He was so smitten that he could hardly speak her name.