let in on


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Related to let in on: in the wrong, pay a visit, ahead of schedule, stop short of, so much for

let in on

Allow someone to know about or participate in something, as in I'm going to let you in on a little secret. This idiom was first recorded in 1904.
See also: let, on

let (someone) in on

1. To reveal (a secret) to someone: They finally let me in on their plans.
2. To allow someone to participate in (something).
See also: let, on