conspiring

kənˈspʌɪə

verb

make secret plans jointly to commit an unlawful or harmful act.

they conspired against him

plot,hatch a plot,form a conspiracy,scheme,plan,lay plans,intrigue,collude,connive,collaborate,consort,machinate,manoeuvre,be/work hand in glove,abet,be an accessory,be in cahoots,cabal