Common meaning:

Someone who knows the right way to do something.

Hidden meaning of the Equity religion: 

A power play to silence minoritized voices.

Discussion:

The Equity believers think that the powerful use the concept of expertise as a tool to silence the minoritized.

Like everything in the Equity world, people who have expertise are viewed on an oppression scale. Anyone who has achieved expertise in a subject is not viewed with admiration, but is considered to be an oppressor. In education, this has manifested itself in the devaluation of the knowledge of the teacher. Educators are attacked with the trite saying, “Not the sage on the stage, but the guide on the side.” 

Students are considered to be the oppressed and their voices are the only ones in the classroom that can speak truth. The teacher needs to be silent and allow students to discover knowledge for themselves. There is great value in self-discovery, but what is really going on here is Equity beliefs have infected the education process and devalued expertise. Any teacher or expert who tries to tell people what they need to know is engaging in a power play. 

Listening to someone who is a novice, because they are part of a particular group, over someone who has studied a topic for years, is insane.