The marsh was often alive with ignes fatui that led travelers astray at night.

Despite the serious topic, his presentation was marred by gratuitous fatuities that distracted the audience.

Her fatuitous remark derailed the serious discussion.

Her fatuity during the negotiations cost the company dearly.

Her fatuitousness at the meeting undermined the team's credibility and stalled progress.

Despite the advisor's protestations, the committee's decision reflected a surprising fatuism that shocked the experts.