In secret
Definition 1 of 1
Pro Tip 1/3Hidden Agendas
Used when discussing actions or plans not revealed to everyone, suggesting a layer of secrecy. 
The committee's decision was made in secret, causing mistrust among the members.
Pro Tip 2/3Exclusive Knowledge
Highlights that the information or action is only known to a particular group or individual. 
The recipe was passed down in secret within the family for generations.
Pro Tip 3/3Emotional Weight
Indicates something may be emotionally significant due to being hidden, often carrying a sense of burden. 
She kept her illness in secret, not wanting to worry her family.