تخارس

[He feigned himself dumb, or speechless,] is from خَرِسَ المَجْلِسُ: hence إِذَا شَهِدْتَ مَنْ لَا يَفْهَمُ عَنْكَ فَتَخَارَسٌ [When thou art present with, or beholdest, him who will not understand what thou sayest, then feign thyself dumb, or speechless]. (A.)