under the rose

under the rose

Privately, confidentially, or in secret. From the Latin phrase sub rosa, itself referring to the ancient use of the rose as a symbol of secrecy. No, I had no idea they were planning to reject the proposal. They must have reached that decision under the rose. As president, keeping one's tax information under the rose is not illegal, but it is widely seen as ethically questionable.
See also: rose
Farlex Dictionary of Idioms.

under the rose

in confidence; under pledge of secrecy. archaic
The origin of the rose as an emblem of secrecy is uncertain; the concept may have originated in Germany and there was a similar expression in early modern Dutch. Under the rosse appears in a 1546 State Paper of Henry VIII , with a gloss that suggests that it was then a new or unfamiliar expression. The Latin equivalent sub rosa has also been very commonly used in English since the mid 17th century in this metaphorical sense.
See also: rose
Farlex Partner Idioms Dictionary

under the rose

Sub rosa.
See also: rose
American Heritage® Dictionary of the English Language, Fifth Edition.
See also:
  • sub rosa
  • (as) sure as eggs (is eggs)
  • a penny for them
  • great minds
  • great minds think alike
  • be twiddling (one's) thumbs
  • be twiddling your thumbs
  • 57
  • Heinz 57
  • Heinz 57 (variety)