مُعْتَتَبٌ

[is used, agreeably with analogy, in the sense of the verbal noun of اِعْتَتَبَ]. El-Kumeyt says,

الشَّوْقُ مِنْ فُوءَادِى وَالش ↓ فاعْتَتَبَ

شِعْرُ إِلَى مَنْ إِلَيْهِ مُعْتَتَبُ

[And desire turned away from my heart, and my poetry unto him unto whom was its turning]. (S, O.)