Definition of sub rosa in English:

sub rosa

adverb & adjective

formal
  • Happening or done in secret.

    as adverb ‘the committee operates sub rosa’
    as adjective ‘sub rosa inspections’
    • ‘Sub Rosa is a Latin term meaning secrecy, literally translating to ‘under the rose’. The rose in ancient times was a symbol of sworn confidence of participants at a meeting.’
    in secret, secretly, in private, privately, in confidence, confidentially, behind closed doors, surreptitiously, discreetly, furtively, clandestinely, on the quiet, on the sly, unofficially, off the record, between ourselves
    View synonyms

Origin

Latin, literally ‘under the rose’, as an emblem of secrecy.

Pronunciation

sub rosa

/ˌsəb ˈrōzə//ˌsəb ˈroʊzə/