discursion

他的演讲因随意的离题漫谈而难以跟上。

His lecture was hard to follow because of its casual ___discursion.

她不喜欢那篇文章的散漫离题，觉得缺乏重点。

She disliked the article's rambling ___discursion, finding it unfocused.

在紧张的讨论中，这种离题漫谈浪费了宝贵的会议时间。

During the tense debate, such ___discursion wasted precious meeting time.