in secret—
1. secretly; in private:
- Men of the most different characters … resemble each other in the practice of nursing in secret some pet superstition.
2. in strict confidence:
- This story is told in secret, as it were, because the people were afraid to tell it openly.
in the secret—(predic.) sharing a secret; privately aware of smth.:
- One of her maids who was in the secret revealed the truth.