There are various types of “abandonment” of the Qurʼan:
1. To abandon listening to it and believing in it.
2. To abandon acting upon it, and ignoring its lawful and prohibited ordinances (halal and haraam), even if one believes in it and recites it.
3. To abandon judging by it, and resorting to it as a judge when there are differences in the essence of the religion or other matters.
4. To abandon pondering over it, and understanding it, and seeking the explanation of it.
5. To abandon using it as a cure in all types od diseases of the heart, and instead to seek to cure these diseases by other means.
And all of these categories are included in the statement of Allāh:
“And the Messenger (will) say: O My Lord, indeed my people took this Qurʼan as something worthy of being abandoned.” [25:30]
Even though some of these types of abandonment are worse than others.
Reference : An Introduction To The Sciences Of The Qurʼan, quoting from: Ibn Al-Qayyim