jiǎ​tú​miè​guó

to betray an ally

假途灭虢 假途滅虢 jiǎ​tú​miè​guó
to betray an ally
literally "to borrow a path to conquer Guo"; to use a neighbor as a stepping stone to destroy a third party, then turn and conquer the neighbor; to connive with someone to damage a third party and then turn on the partner

Frequency

Written text
0.007 per million

Sources

Frequency data
BCC Corpus (BLCU)