Polytheism or shirk refers to a partner to Allah (SWT) in worship, Leadership, or His attributes or name. It also appears among one of the destructive sins, as told by Allah SWT in the Holy Quran in Surah (4:48)
The second destructive and major sin is to practice magic which is strictly prohibited in Islam. It is also known as Sihr, an Islamic term. It sets on everything the reason for which is hidden and everything that can be imagined by saying or comparing that takes place as hypocrisy.
A verse from the Holy Qur’an clearly states that the magician only deceives the eye of the person and makes them think that they followed a real trick yet, it is only an illusion. Therefore, magic, including all its types and forms, is major sins.
Murdering someone or taking someone’s life unjustly is a major sin, as it enhances violence, chaos, and disorder in society. Islam, the divine religion, maintains the blood of the Muslims and secures the societies from such chaos and violence. Islam denies us from shedding the blood of innocent people.
People who accuse pure women unjustly of committing adultery and illegal intercourse are cursed in the world and hereafter and deserve serious punishment. In the Quran, it is mentioned in Surahs (24:4 - 5)
Having intimate relations outside of wedlock or marriage is a sin.
Suicide is a sin in Islam as stated in the Quran in Surahs 4:29-30