Ketubot 72B

קלתה שפיר דמי, דת יהודית ⁠— אפילו קלתה נמי אסור.

if she covers her head with her basket [kilta], it seems well and is sufficient. But by precepts of Jewish women, i.e., custom, even if her head is covered by her basket this is also prohibited; she requires a substantial head covering.

אמר רבי אסי אמר רבי יוחנן: קלתה, אין בה משום פרוע ראש. הוי בה רבי זירא: היכא? אילימא בשוק ⁠— דת יהודית היא! ואלא בחצר ⁠— אם כן לא הנחת בת לאברהם אבינו שיושבת תחת בעלה! אמר אביי ואיתימא רב כהנא: מחצר לחצר ודרך מבוי.

R' Asi said that R' Yoḥanan said: If she covers her head with her basket, there is no violation of the prohibition against having an uncovered head. R' Zeira discussed it: Where is the woman that R' Yoḥanan is referring to? If we say he means that she appears this way in the marketplace, this is a violation of precepts of Jewish women, as explained previously. And if you say rather that he means she appears this way in her own courtyard, if so, you have not allowed any daughter of our father Abraham to remain with her husband, since most women are not careful to cover their heads completely inside their own courtyards. Abaye said, and some say that Rav Kahana said: R' Yoḥanan is referring to when she walks from one courtyard to another courtyard or via an alleyway. Although these places are not considered public areas, strangers may still be present in them.

וטווה בשוק. אמר רב יהודה אמר שמואל: במראה זרועותיה לבני אדם. רב חסדא אמר אבימי: בטווה ורד כנגד פניה, ומדברת עם כל אדם. אמר רב יהודה אמר שמואל: במשחקת עם בחורים.

§ And the Mishnah stated that a woman violates Jewish custom if she spins wool in the marketplace. Rav Yehuda said that Shmuel said: This means that she reveals her arms to people by raising her sleeves as she spins. Rav Ḥisda said that Avimi said: It is referring to when she spins with a red [vered] thread opposite her face to highlight her beauty, which entails an element of promiscuity. The Mishnah also stated another violation of Jewish custom: Or she speaks with every man she encounters. Rav Yehuda said that Shmuel said: This means that she flirts with young men.