English translation (word)
guest-friend, host, stranger
English translation (etymon)
to carve, to shave
Etymologicum Gudianum, xi 414.45-46, 415.5
F.W.Sturz, Etymologicum Graecae linguae Gudianum et alia grammaticorum scripta e codicibus manuscriptis nunc primum edita, Leipzig: Weigel, 1818
<Ξένος>, παρὰ τὸ ἔξω ἰέναι, ἢ παρὰ τὸ ἐκτὸς τῆς ἑνότητος· ἢ παρὰ τὸ ξέω, ὁ ἐξεσμένος καὶ ἀποκεχωρισμένος·[…] <Ξένος>, παρὰ τὸ ἔξω εἶναι
xenos ("host"),from "to go abroad" (exō ienai) or from "out of the unit" (ektos tēs enotētos); or from "to carve" (xeō), the person who is "rubbed away" (exesmenos) and completely separated […] xenos (host), from "to be outside" (exō einai)
See Etymologicum Magnum 503, line 19-21 Kallierges, with the compound καταξέω (polish smooth or rub away?) in the entry κενός : …Ἢ παρὰ τὸ χέω, χενὸς καὶ κενός· ἢ παρὰ τὸ ξέω, ξενὸς ὁ κατεξεσμένος, καὶ κενός (cf. Et. Gudianum, p. 314.31 Sturz : ἢ ξένος ὁ κατεξεσμένος καὶ κενός)
Ξένος (Ionic ξεῖνος) is from ξένϝος. It may go back to *ghs-en-, displaying the zero grade of *ghes- found in Lat. hostis "stranger, enemy", hopes "host", Got. gasts "host". Beekes (EDG) thinks it is Pre-Greek.
Persistence in Modern Greek
The word survives in Modern Greek designating: 1. 'not mine', 2. 'foreign', 3. 'unknown, or guest'. Plural neuter "τα ξένα" and fem. ξενιτιά mean 'foreign land of migration'. There also are many derivatives and compounds like ξενίζω, ξενόφερτος etc.
This etymology takes the word back to a simple verb, ξέω, whereas most etymologies parse it as a compound of "outside". The link with ξέω is unexpected: the verb is understood in a metaphoric meaning which can hardly be applied to a human being. It relies on the basic notion that the stranger is separated from his community, and then the etymologist tried to find a word which could mean "separate" and was phonetically close to ξένος