"And the Messenger said: O My Lord my people have abandoned - acting or listening - to the Qur'aan." [Al-Furqaan: 30]
When the Qur'aan was being read to the idol-worshippers they would make noise and futile speech so that they would not hear the Qur'aan. However, this is from the ways of abandoning the Qur'aan.
Likewise not having faith and trust in it is also from the ways of abandoning the Qur'aan. Not pondering over it, nor trying to understand it, not acting by it, not obeying its orders and refraining from what it forbids, turning to something other than it - whether poetry, opinions or music, amusement, or other forms of speech and taking a path that is derived from other than the Qur'aan are all from the ways of abandoning the Qur'aan.