in on

be in on sth اطلاع داشتن از چیزی یا درگیر بودن با چیزی
مثال:
She is in on my secret. او از راز من مطلع است.

مطلع بودن، آگاهی داشتن، دانستن.

— Let Us In On it :
بگوما هم بدونیم.

1 ) knowledgeable about ( something ) or involved in ( something ) They were all in on the scheme. I let them in on our little secret
Merriam - Webster dictionary@

2 ) in on sth
involved with or knowing about a particular activity or plan:
He seems to be in on everything that happens at work.
She's trying to get in on a research project organized by the university
Cambridge dictionary@

3 ) be in on something
to take part in something that is being planned or discussed
I don’t know what they agreed to because I wasn’t in on the deal
Macmillan dictionary@

4 ) be/get in on something
to be or become involved in something that is happening
I think you ought to be in on this discussion, Ted
Longman dictionary@