incognito

with one's identity concealed

The ancient Greeks and Romans knew that there were times when you didn't want to be recognized. For example, a myth tells how Zeus and Hermes visited a village incognito and asked for lodging. The apparently penniless travelers were turned away from every household except that of a poor elderly couple named Baucis and Philemon, who provided a room and a feast despite their own poverty. The Romans had a word that described someone or something unknown (like the gods in the tale): incognitus, a term that is the ancestor of our modern incognito.