If shirk (associating partners with Allah) is mentioned in many Qur'anic texts, the intended meaning is kufr (disbelief).

The Shaykh : There is one more point to make after we have understood the meaning of shirk (associating partners with Allah), which I indicated is a linguistic meaning. It is clear that shirk means making a partner for something else; here, it means making a partner alongside Allah (Mighty and Majestic). However, we must know that in many Qur'anic texts and Prophetic hadiths, the term shirk is used without intending its linguistic meaning, but rather the meaning of kufr (disbelief) in its entirety. That is, it is intended that anyone who associates a partner with Allah through any doctrinal deviation that contradicts Islam is a mushrik (one who associates partners with Allah). For example, a clear example, since time is running out, is a person from those who are called "worshippers of Allah according to the religion of nature." They believe that this universe has one Creator with no partner, but they denied the prophethoods and denied the resurrection and the rising. Are these people mushrikin or kafirun (disbelievers)? If we look at the linguistic meaning, they are kafirun and not mushrikin, because they did not make a partner alongside Allah. However, they made a partner alongside Allah in the form of their minds and their desires when they denied the religious truths with which Allah sent His prophets and messengers, such as the Books, the messengers, the Scrolls, and the like. Even clearer than this is a Muslim who testifies that there is no god but Allah and that Muhammad is the Messenger of Allah, and who understands tawhid (the oneness of Allah) with this clear and evident meaning, but who denies a verse from the Qur'an, saying, "This did not enter my mind, and my heart did not digest it." This is kufr (disbelief) without a doubt, but he is also a mushrik. This has another detailed explanation, which I hope to elaborate on for you in the next lesson if you remind me of it, because it removes some doubts from you. The previous verse says: Some people have said, "Then Allah forgives kufr (disbelief) because He said: So if it is kufr (disbelief) that does not involve shirk (associating partners with Allah), He forgives it, and it falls under the generality of His statement: But if you know that kufr (disbelief) is shirk (associating partners with Allah) and that shirk (associating partners with Allah) is kufr (disbelief) in the Shari'ah, and there is no difference between them, then when you recite this verse , whether you interpret it as "associates partners" or "commits kufr (disbelief)," the meaning is the same.