There was a subtle tone of secret humor in her voice when she agreed to the silly rule.
She is keeping a serious face for everyone else, but secretly finds the whole situation hilarious.
Noun phrase: secret humor
Vibe: Communication style
Jokes, funny observations, or amusement shared quietly between close friends or kept to oneself, hidden from the rest of the group.
They shared a brief look of secret humor during the extremely long speech.
You picture two friends sitting in a boring meeting, making brief eye contact and stifling a laugh over a joke only the two of them understand.
Real-life examples
My brother and I have a secret humor that no one else in the family gets.
This highlights a private connection where shared memories make simple things funny only to them.
Synonyms
Contrast & nuance
Unlike open comedy or loud jokes meant for an entire room, secret humor relies on private connection, quiet restraint, or shared context. It is felt or communicated discreetly rather than performed out loud.