וַתָּסַר֩ בִּגְדֵ֨י אַלְמְנוּתָ֜הּ מֵֽעָלֶ֗יהָ וַתְּכַ֤ס בַּצָּעִיף֙ וַתִּתְעַלָּ֔ף וַתֵּ֙שֶׁב֙ בְּפֶ֣תַח עֵינַ֔יִם אֲשֶׁ֖ר עַל־דֶּ֣רֶךְ תִּמְנָ֑תָה כִּ֤י רָאֲתָה֙ כִּֽי־גָדַ֣ל שֵׁלָ֔ה וְהִ֕וא לֹֽא־נִתְּנָ֥ה ל֖וֹ לְאִשָּֽׁה׃
Entonces quitó ella de sobre sí los vestidos de su viudez, y cubrióse con un velo, y arrebozóse, y se puso á la puerta de las aguas que están junto al camino de Timnath; porque veía que había crecido Sela, y ella no era dada á él por mujer.
Rashi
ותתעלף AND SHE WRAPPED HERSELF — she veiled her face that he should not recognise her.
Chizkuni
ותכס בסעיף, “she wrapped her veil so as to cover her face.” This was not something that widows used to do.
Da'at Zekenim
בפתח עינים, this expression may be understood as we know from the Talmud, tractate Sotah folio,10, where Rabbi Shmuel bar Nachmeni understands it as giving a reason for her apparently inappropriate behaviour, when Yehudah first asked her about her personal status; she said that she was not married, was a widow, that she was ritually pure, and quite unattached to any other man when she had married, and that even then she was not anyone’s daughter-in-law. [The marriage had not been consummated. Ed.]