sail under false colors, to

false colors

The guise of false pretenses, so as to deceive someone or to hide one's true nature or intentions. (An allusion to the identifying flags of a ship, and so usually used in the phrase "sail under false colors.") Primarily heard in US. Tim thought he could just put on fancy clothes and rub elbows with the upper crust that Janet's family socialized with, but everyone at the party knew he was sailing under false colors. I don't want to be accused of flying under false colors, so let me say straight away that I'm being paid to give a review of this product today.
See also: color, false

sail under false colors

To operate using or under the guise of false pretenses, so as to deceive someone or to hide one's true nature or intentions. (An allusion to the identifying flags of a ship.) Tim thought he could just put on fancy clothes and rub elbows with the upper crust that Janet's family socialized with, but everyone at the party knew he was sailing under false colors. I don't want to be accused of sailing under false colors, so let me say that I'm being paid to give a review of this product today.
See also: color, false, sail

sail under false colors

 
1. Lit. to sail with false identification. (Pirates often sailed under the national flag of the ship they planned on attacking.) The ship, sailing under false colors, suddenly started to pursue our ship. Bluebeard the pirate was known for sailing under false colors.
2. Fig. to function deceptively. You are not who you seem to be. You are sailing under false colors. Tom was sailing under false colors and finally got found out.
See also: color, false, sail

false colors

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]
See also: color, false

sail under false colors

see under false colors.
See also: color, false, sail

sail under false colors, to

To behave deceptively; to misrepresent oneself deliberately. The term comes from maritime piracy, rampant from ancient times until about 1825 in Atlantic and Mediterranean waters and still existing in parts of the Pacific. In order to deceive their prey, pirates would run a “friendly flag”—that is, “false colors”—to lure their victims close enough so that they could easily be captured. The term began to be used figuratively in the late seventeenth century. Robert Louis Stevenson used it in St. Ives (1897): “I had so much wisdom as to sail under false colours in this foolish jaunt of mine.”
See also: false, sail