An English surname, from Old Norse from the Old Norse given name Kóri, itself perhaps from Old Irish Cuire, from cuire (“troop, host, company”), from Proto-Celtic *koryos (“army, tribe”), from Proto-Indo-European *ker- (“army”).
"My neighbor Corey introduced me to his grandmother at the family reunion."
The word "corey" comes from Angloromani and ultimately traces back to the Romani language via a Prakrit root meaning "penis." It was adopted into English slang with this original anatomical sense.