串通 (chuàn tōng) is a verb meaning 'to collude' or 'to conspire' — typically implying secret, often dishonest cooperation between two or more people to achieve a shared goal, usually one that violates rules, ethics, or the law. The first character 串 (chuàn) suggests linking or stringing things together, like threading beads; the second 通 (tōng) means 'to connect' or 'to communicate'. Together, they convey the idea of secretly connecting intentions and actions across parties.

This word carries a strong negative connotation and is commonly used in contexts involving fraud, cheating, bribery, or unfair advantage — such as students cheating on exams, employees defrauding their company, or officials accepting bribes with accomplices. It's rarely used neutrally or positively; even informal collusion (e.g., friends jokingly 'fixing' a game result) would sound overly dramatic or sarcastic when described with 串通.