Threat of severe punishment in Hell and deprivation from Paradise for those who neglect Hijab:

4- On the authority of Abu Hurayrah, may Allah be pleased with him, the Messenger of Allah, sallAllahu ‘alayhi wa sallam, said: "There are two types of people who will be punished in Hell and whom I have not seen: [the first type are] men who have flogs like the tails of cows and they beat people with them, and [the second type are] women who are dressed as if naked who will be inclined (to evil) and make others incline (towards it). Their heads will appear like the humps of camels inclined to one side. They will not enter Paradise and they will not smell its fragrance even though its fragrance can be perceived from such and such a distance [from a great distance]." [Muslim]

This Hadeeth implies a severe threat for neglecting Hijab, exposure of women's beauty as well as wearing thin or short clothes. It also implies a severe warning of doing injustice to people or violating their rights. Such women and people will be deprived from entering Paradise.
(whom I have not seen) means during his lifetime. This Hadeeth is one of the miracles of the Prophet, sallAllahu ‘alayhi wa sallam, because now there really are women who are dressed in short clothes and meanwhile they are naked due to the uncovered parts of their bodies. There are also women who are dressed with transparent clothes and veils which do not cover the under parts and therefore they are naked due to unveiling some of their body from under such clothes. Wearing tight clothes which reveal the details of the woman's body and beauties is similar to nakedness or even more harmful in terms of temptation.

(inclined): means that they deviate from obeying Allah The Almighty and safeguarding what they are required to safeguard. (make others incline) means that they are also teaching other women this dispraised action.

It is also said that the meaning of "inclined" is that they make tilted hairstyles like immoral women, and make this for other women too.

(Their heads will appear like the humps of camels): this means that they make their heads appear larger by wrapping a headband or the like around it. This is similar to what many women do nowadays who collect their hair at the top of their heads or on their foreheads, and so on. We seek refuge in Allah from both hidden and apparent temptations.

The harmful effects of neglecting the Hijab:

Given the aforementioned explanation, neglecting the Hijab is harmful to both women and men in both worlds. It renders the woman disdainful and indicates her ignorance, and it is forbidden for the young, the old, the beautiful and all other women. Neglecting the Hijab entails great harm and grave danger as it destroys homes, brings about disgrace and shame and calls to temptation and destruction. A woman who neglects Hijab has followed the steps of the devil, contradicted the commands of the Sunnah and the Quran, violated the Limits of Allah The Almighty and dared to indulge in dissolution and disobedience.

What saddens the heart and brings tears to the eyes is that we see some girls unveiling their faces, arms and legs in streets, hospitals, the Two Holy Mosques as well as in other places while paying no attention to the commands of Allah The Almighty and His Messenger, sallAllahu ‘alayhi wa sallam, which forbid neglecting the Hijab and exposure of women's beauty and command covering and adherence to the Hijab.

O Muslim sister, adhere to the Hijab and avoid exposure of your beauty before non-Mahram men and before leaving your home frequently without a Sharee‘ah-approved justification. You have to do that in order to be obedient to Allah The Almighty and His Messenger, sallAllahu ‘alayhi wa sallam, and safeguard yourself, your religion and honor from indecency and disdain.

One of the worst aspects of corruption is how a lot of women imitate non-Muslim women from among the Christians and the likes of them who wear short clothes, display their hair and body, and while imitating the hairstyles of non-Muslims and immoral women, parting their hair on the side and wearing artificial hair, which is called a "wig". In a Hadeeth, the Prophet, sallAllahu ‘alayhi wa sallam, said: "Whoever imitates a people becomes one of them." [Ahmad, Abu Daawood, Ibn Hibbaan: Saheeh (Authentic)]