وَإِذَا رَأَيْتَ ٱلَّذِينَ يَخُوضُونَ فِىٓ ءَايَٰتِنَا فَأَعْرِضْ عَنْهُمْ حَتَّىٰ يَخُوضُوا۟ فِى حَدِيثٍ غَيْرِهِۦ
"When you see those who plunge into talk about Our signs, turn away from them until they plunge into some other talk."
The خ-و-ض root: to wade into water and walk on; and to plunge into a piece of talk. The root was treated in al-Zukhruf, al-Ṭūr, al-Maʿārij and al-Muddaththir.
And the limit of the command is worth recording: ḥattā yakhūḍū fī ḥadīthin ghayrih — until they pass to some other talk.
I record this as my own reading: the turning away is not without term; it is tied to the subject. And it is tied not to persons but to what is being said. That is, the separation is not set up as a permanent break.
The same field was treated at al-ʿAnkabūt 29/46 (wa lā tujādilū ahla'l-kitābi illā bi'llatī hiya aḥsan) and at al-Furqān 25/72 (wa idhā marrū bi'l-laghwi marrū kirāmā). The three verses are read together: one states the method of dispute, one the passing by of idle talk, and one how long one is to keep away.