IPA: /kəˈluːsɪvli/
KK: /kəˈluːsɪvli/
In a way that involves secret or illegal cooperation between people or groups, often to deceive others.
The companies collusively agreed to fix prices, which is illegal.
Collusively → It is formed from "colludere" (meaning to play together or conspire) and the suffix "-ly" (which turns an adjective into an adverb). The word "collusively" means in a manner that involves secret or deceitful cooperation between parties.
Think of 'playing together' ('colludere') in a secretive way — that's why collusively means acting in a conspiratorial manner.