«وَكِدْتُ أُفْصِحُ عَنِ افْتِنَانِهِ وَإِثْمَارِ أَفْنَانِهِ»
I almost revealed his artistic versatility and the fruitfulness of his many branches.
Iftinān means variety of artistic modes; ithmār afnānih pictures those talents as fruit-bearing branches.
Al-Ḥārith appreciates the elder’s skill but fears that disclosure of his earlier tricks could jeopardize the kindness now shown to him.