There are a number of religious prohibitions in Sikhism for a Sikh.
1.Cutting hair: Cutting or removing hair from any body part is strictly forbidden for Sikhs by the Sikh Temple governing board and not the Sikh Religious texts.
2.Intoxication: Consumption of alcohol, drugs, tobacco, and other intoxicants is not allowed. Intoxicants are strictly forbidden for a Sikh.
3.Blind spirituality: Superstitions and rituals should not be observed or followed, including pilgrimages, fasting and ritual purification; circumcision; idols, grave worship; compulsory wearing of the veil for women; etc. Observation of the 5 K’s, is not considered blind superstition.
4.Material obsession: Obsession with material wealth is not encouraged in Sikhism.
5.Sacrifice of creatures: The practice of sati (widows throwing themselves on the funeral pyre of their husbands), ritual animal sacrifice to celebrate holy occasions, etc. are forbidden.
6.Non-family-oriented living: A Sikh is encouraged not to live as a recluse, beggar, yogi, monastic (monk/nun) or celibate.
7.Worthless talk: Bragging, gossip, lying, slander, “back-stabbing”, etc. are not permitted. The Guru Granth Sahib tells the Sikh, “Your mouth has not stopped slandering and gossiping about others. Your service is useless and fruitless.”
8.Priestly class: Sikhism does not have priests, they were abolished by Guru Gobind Singh (the 10th Guru of Sikhism). The only position he left was a Granthi to look after the Guru Granth Sahib; any Sikh is free to become Granthi or read from the Guru Granth Sahib.
9.Eating meat killed in a ritualistic manner (Kutha meat): Sikhs are strictly prohibited from eating meat killed in a ritualistic manner (such as halal or kosher, known as Kutha meat ), or any meat where langar is served. In some small Sikh Sects, i.e. Akhand Kirtani 10.Jatha eating any meat is believed to be forbidden, but this is not a universally held belief. The meat eaten by Sikhs is known as Jhatka meat.
11.Having extramarital sexual relations