וַתֹּֽאמֶר־לָ֥הּ בַּת־פַּרְעֹ֖ה לֵ֑כִי וַתֵּ֙לֶךְ֙ הָֽעַלְמָ֔ה וַתִּקְרָ֖א אֶת־אֵ֥ם הַיָּֽלֶד׃
바로의 딸이 그에게 이르되 가라 그 소녀가 가서 아이의 어미를 불러오니
Rashi
ותלך העלמה AND THE YOUNG WOMAN WENT — she went eagerly and with vigour (עלמות) like a young man (עלם) (cf. Sotah 12b).
Chizkuni
ותלך העלמה, “the young lady went, etc.” The reason why the Torah calls her by the description עלמה, is because she concealed the fact that she was the baby’s sister.