1. past tense of 'manter em segredo': to keep something hidden, concealed, or confidential; to not reveal or disclose information
She kept the surprise party secret from her husband.
Ela manteve a festa surpresa em segredo do seu marido.
2. to preserve confidentiality about a matter or information
They kept the business deal secret until the announcement.
Eles mantiveram o acordo comercial em segredo até o anúncio.