«تَعَضُّ بَنَانَ النَّادِمِ الْحَصِرِ»
She bites her fingertips like someone overtaken by regret and helplessness.
Banān denotes fingertips; al-nādim is a person filled with regret, and al-ḥaṣir conveys distress or constrained helplessness. The imperfect verb taʿaḍḍu makes the gesture feel immediate and continuing.
Instead of merely naming grief, the poet shows an action associated with it. The gesture turns an inward emotional state into a vivid physical detail.