amigo secreto

Etymology
lit. 'secret friend'.

Noun

 * 1)  secret Santa a Christmas tradition where a group of people give anonymous gifts to each other, with each person randomly selected to give a gift to one other person
 * 2) secret Santa the person who buys a present for another in a secret-Santa exchange
 * 1) secret Santa the person who buys a present for another in a secret-Santa exchange