Tutoring English, I constantly await new vocabulary discoveries. The tutor shares the meaning of sub rosa.
sub rosa: (adverb) covertly; secretly
Sub rosa, in Latin, has the literal meaning “under the rose.” Roses carried the implication of confidentiality even in ancient times; a room might be stocked with roses before a meeting to remind attendees not to share what’s said there.
Gilmour, Lorna (editor). Collins Essential Canadian English Dictionary & Thesaurus. Glasgow: HarperCollins, 2006.
Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.