collude
verb
[ kəˈl(j)uːd ]
• cooperate in a secret or unlawful way in order to deceive or gain an advantage over others.
• "he accused his opponents of colluding with one another"
Similar:
conspire,
connive,
intrigue,
be hand in glove,
plot,
participate in a conspiracy,
collaborate,
scheme,
be in cahoots,
machinate,
cabal,
complot,
Origin:
early 16th century: from Latin colludere ‘have a secret agreement’, from col- ‘together’ + ludere ‘to play’.