in league with

in league with or  {informal} in cahoots with  {prep.}
In secret agreement or partnership with (someone); working together secretly with, especially for harm.
People once believed that some women were witches in league with the devil.
The mayor's enemies spread a rumor that he was in cahoots with gangsters.
Categories: informal preposition
Source: A Dictionary of American Idioms

Subscribe to: American Idioms