The verbal noun is اِدْهِيْمَامٌ.
Its meaning in this level is to become intensely black or very dark.
So اِدْهَامَّ describes becoming intensely dark.
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Masdar and Meaning
Derived Trilateral (with Hamzah) - Bab 5: If'eelaal (Idheemam)
The verbal noun is اِدْهِيْمَامٌ.
Its meaning in this level is to become intensely black or very dark.
So اِدْهَامَّ describes becoming intensely dark.