To discuss an existing but unacknowledged topic.
Tim is this an elephant in the room week.......Rowleys has been de-elephanted! Now you are suggesting another elephant has arrived,
—Bloodtangerine, “The Parky update post,” Fansonline, February 11, 2014
Neologism of the day: de-elephantify (as in de-elephantify the room) Talk about that thing we know is there but don’t usually acknowledge.
—David Lutz, “Neologism of the day...,” Twitter, February 11, 2014
I spent a couple days this past week on the phone connecting with each of the campus ministry leaders in LA and Orange County. In one of the conversations, one of the leaders said this:
“I just had to de-elephantize it...”
What he meant was, there was an issue out there that he knew would be an issue if he didn‘t call it out. There was an elephant in the room.
—Bob Fuhs, “Where’s the Elephant?,” Bob Fuhs, September 20, 2009
The verb comes from the phrase "the elephant in the room" (or sometimes "the elephant in the living room"), which (in the more common sense) refers to a topic or issue that obviously exists but remains unacknowledged because it's just easier or more comfortable to do so. This sense of the phrase is not as old as you might think, with the earliest OED cite only going back to 1984.
Judging by the lexical evidence, the verb de-elephant is most often used to refer to getting off an elephant that one has been riding:
Our elephants led us to an open area where we de-elephanted.
—Megan Tsang, “Raddest photo trip ever,” Megan Tsang Studio, December 13, 2009