Xenofon’s name day is January 26, the feast of Xenophon.
Churches that follow the Old (Julian) Calendar keep the same feast on February 8 of the civil calendar. See everything commemorated on January 26.
The saint behind the name

Xenophon
January 26, Venerable, Ξενοφών
St. Xenophon was a devout and wealthy man of Constantinople in the sixth century, who with his wife Mary raised their two sons, Arkadios and John, in the fear of God. When the young men were shipwrecked on a voyage to their studies, each was saved without the other's knowledge, and each in gratitude took up the monastic life in the Holy Land.
Also celebrating on January 26
These names share the feast, many of them other forms of the same name:
What to say on a name day
The Greek wish is Χρόνια Πολλά (Chronia Polla), “many years.” A call or a short message on the day is what people remember. See name day wishes you can send and what a name day is.