"The hidden Trump vote in this country is a very significant proposition."
Pressed on how big that hidden vote is, Conway said she "can't discuss it."
"It's a project we're doing internally. I call it the undercover Trump voter, but it's real," she said.
A portion of her remarks were rebroadcast on MSNBC and posted by Mediaite.
"People who are supporting Donald Trump, who have not voted Republican in the past, who have not voted in quite a while, are so tired of arguing with family and friends and colleagues about their support of Donald Trump that they just decided not to discuss it," Conway further explained, The Guardian reports.
"We give people a comfortable way to express that maybe they don't want to vote this year and why that is," she added.
As a result, Conway asserts, she could reach these undercover voters "in many different ways … We go to them where they live, literally."
The Guardian notes the political phenomenon is known as "the Bradley effect," named after former Los Angeles mayor Tom Bradley, who was favored in polls in California's 1982 gubernatorial election over his white Republican opponent, George Deukmejian, before suffering a narrow shock loss on election day.
In an averaging of national polls, Hillary Clinton leads Trump by about six points.