Are the laws of tznius clearly defined for women? I see very different approaches ti tznius in very different communities. Is tznius based on the community – and what may be tznius in one community is not tznius in another? Or is there debate on how machmir one needs to be? If so, what is the basic halacha when it comes to clothes for a woman.
The basic criteria of tzenius are defined by Chazal: The two elements pointed out are the hair, and the thigh. The Gemara (Kesubos 72) also mentions the arm, which must also be covered.
With regard to hair, poskim explain that this applies specifically to married women (even after divorce), and not to unmarried women.
Although there is an opinion that maintains that the principles of tzenius are relative, and changes in social norms can lead to changes in the principles (see Divrei Chamudos, Rosh Berachos 3:37), the majority of poskim write that these principles do no change with the times, and they are rather fixed. Therefore, even if all women wear sleeveless clothes, this remains peritzus, and the obligation to cover one’s arms remains.
Therefore, a woman must be careful to have sleeves long enough to cover the arm, and a skirt long enough to reach beneath the knee, even when she is sitting. The neckline must likewise not be too low.
For other parts of the body, the halachah depends on the custom; in places where there is a custom to cover a part of the body, the laws of tznius will obligate this. Where there is no custom (for instance, for the forearm), there is no obligation to cover the area.
It should be noted that the concept of tzenius is very central to Torah practice, and it is an area that requires chizuk and chinuch.
Moreover, it is important that the principle of tzenuis — the concept of seeing beyond the superficial body, and the awareness that sexual attraction is something reserved for the husband-wife relationship — should get through, rather than only formalistic dress codes.