Definition of sub rosa in English:

sub rosa

adjective & adverb

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
    in camera
    à huis clos
    in petto
    on the q.t., between you, me, and the bedpost, and the gatepost
    under the rose
    View synonyms

Origin

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

Pronunciation:

sub rosa

/sʌb ˈrəʊzə/