وَالْإِلْهَامُ الْمُفَسَّرُ بِإِلْقَاءِ مَعْنًى فِي الْقَلْبِ بِطَرِيقِ الْفَيْضِ
Inspiration is explained as the casting of a meaning into the heart by way of an inward influx.
Ilqāʾ suggests that a meaning is received inwardly; the heart denotes the seat of inward apprehension in this discussion. The definition does not require an audible statement, direct sense perception, or ordered premises. That differentiates inspiration from the three previously discussed means.
Someone may suddenly feel convinced that they should apologize for an injury. Describing that inward experience is one thing; attributing its exact source to God, or making it binding law for other people, makes additional claims that require justification.