noun, noun or participle which takes 'suru', intransitive verb
secret understanding; collusion; betrayal
Refers to secretly cooperating with an enemy or outsider, often involving betrayal of one's own group. Used in historical, political, or dramatic contexts.
彼は敵と内応して城を明け渡した。
He colluded with the enemy and surrendered the castle.
The retainer was captured on suspicion of secret collusion.