Praise be to Allaah.

The scholars are agreed that it is permissible for women to wear and use pure silk, and that it is haraam for men to do so, because of the hadeeth of ‘Ali ibn Abi Taalib (may Allaah be pleased with him), who said that the Prophet (peace and blessings of Allaah be upon him) took a piece of silk in his right hand and a piece of gold in his left, held them aloft and said: “These are haraam for the males of my ummah and permitted for the females.”

Abu Moosa (may Allaah be pleased with him) reported that the Prophet (peace and blessings of Allaah be upon him) said: “Gold and silk have been permitted for the females of my ummah and forbidden for the males.” Indeed, a stern warning has been narrated concerning this matter, as was reported by al-Bukhaari (5853) and Muslim (2069) in the hadeeth of Ibn ‘Umar (may Allaah be pleased with them both), who reported that the Prophet (peace and blessings of Allaah be upon him) said: “Silk is only worn in this world by the one who will have no share of the pleasure of the Hereafter.” Anas (may Allaah be pleased with him) reported that the Prophet (peace and blessings of Allaah be upon him) said: “Whoever wears silk in this world will not wear it in the Hereafter.”

The scholars allowed men to wear silk in certain exceptional circumstances where there is shar’i evidence to support this, such as Muslim combatants in war who are allowed to wear silk in order to show off and annoy the enemy, which is a kind of psychological warfare. People who are sick may also be permitted to wear silk to relieve their suffering, as Anas reported that the Prophet (peace and blessings of Allaah be upon him) allowed ‘Abd al-Rahmaan ibn ‘Awf and Ibn al-Zubayr (may Allaah be pleased with them both) to wear silk because of a skin irritation that they suffered from.

The scholars also allowed men to wear garments containing four fingers’ width of silk, because of the hadeeth of ‘Umar ibn al-Khattaab (may Allaah be pleased with him) who said that the Prophet (peace and blessings of Allaah be upon him) forbade the wearing of silk except for an area the width of two fingers, or three or four.”

With regard to the matters mentioned in the question, the issue is not what a thing is called but what it really is. If the item that a man is going to wear is made of natural silk, then it is not permissible for him to wear it, no matter how it looks or feels, and no matter whether it is a shirt, pants, socks, a necktie or anything else. And Allaah knows best.