shàng​xià​qí​shǒu

colluding

上下其手 shàng​xià​qí​shǒu
colluding idiom
to practice fraud through collusion or to manipulate a situation or documents behind the scenes for illicit gain
signaling idiom
to raise and lower one's hand as a conspiratorial hint or secret signal to a collaborator

Frequency

Written text
0.182 per million

Sources

Definitions
CC-CEDICT
Frequency data
BCC Corpus (BLCU)