secret understanding

See: collusion
References in classic literature ?
I am sorry to see a secret understanding established already between you and Mr.
The question is whether we have or have not a secret understanding with France, and if so, how far she will be bound by it.
"There is some secret understanding between them," thought the old lady, "and she's to blame; the women always are!"
Possibly he counted on Gania's complaisance; for Totski had long suspected that there existed some secret understanding between the general and his secretary.
"Ah, I always thought there was some secret understanding in that quarter!" And she greedily read the following few lines:
It seemed wrong that there should exist a secret understanding between my husband's friend and me, unknown to him, of which he was the object.
As if there were a secret understanding between herself and Clennam of the most thrilling nature; as if the first of a train of post-chaises and four, extending all the way to Scotland, were at that moment round the corner; and as if she couldn't (and wouldn't) have walked into the Parish Church with him, under the shade of the family umbrella, with the Patriarchal blessing on her head, and the perfect concurrence of all mankind; Flora comforted her soul with agonies of mysterious signalling, expressing dread of discovery.
He often surprised those he met by his significantly happy looks and smiles which seemed to express a secret understanding between him and them.
Summary: Hyderabad (Telangana) [India], Aug 14 (ANI): Bharatiya Janata Party (BJP) MLC N Ramchander Rao on Wednesday said that there is a secret understanding between the Telangana Rashtra Samithi (TRS) and the Congress party.
Reacting strongly to the development, Kejriwal accused the Congress of having a "secret understanding" with the BJP.
Piecing together the evidence, he felt there had been some sort of secret understanding 'in confidential conversation between Gandhi and Bhutto'.
People of India have a genuine question for PM Modi as to why the husband of Nita (first cousin of Anil Ambani) is being protected by PM Modi and RSS and apart from this protection of fugitive what is the other secret understanding between PM Modi and Ambani.