false colors

American  

plural noun

1. the flag of a country other than one's own, especially when used deceptively.

   sailing under false colors.

2. false or deceptive actions or statements; misrepresentation.

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false colors Idioms  

1. Pretense, misrepresentation, or hypocrisy; deceptive statements or actions. For example, She's sailing under false colors—she claims to be a Republican, but endorses Democratic legislation. This term alludes to the practice of pirate ships sailing under false colors —that is, running a particular flag specifically to lure another vessel close enough to be captured. [Late 1600s]

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Etymology

Origin of false colors

1565–75, for literal sense

Example Sentences

He is however flying under false colors, and his constantly shifting stories are as bemusing to Jane as they are amusing to the audience.

From Los Angeles Times

During the campaign, Mr. Trump called for a temporary ban on all Muslim immigration, and as president he has tried to halt entry from Syria and a handful of other Muslim-majority countries, contending that some of the refugees and other migrants could be terrorists trying to slip into the United States under false colors.

From New York Times

Woolsey said on CNN that he did not want to “fly under false colors” any longer.

From Washington Post

This process lets the team get a more detailed view of surface features — the false colors help scientists understand the boundaries of different geological regions.

From The Verge

Flying under the false colors of religious liberty, the five Catholics in the majority insisted they were acting to protect the constitutional rights of two closely held corporations owned and operated by Christian families.

From Washington Times