the GNU version of the Collaborative International Dictionary of English
verb-intransitive. To have secretly a joint part or share in an action; to play into each other's hands; to conspire; to act in concert.
The Century Dictionary and Cyclopedia
To conspire in a fraud or deception; act in concert through a secret understanding; play into one another's hands. See collusion.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
v. act in unison or agreement and in secret towards a deceitful or illegal purpose
Word Usage
"The U.S. Department of Justice says it has launched a new investigation into price-fixing in the industry, examining whether record labels collude to keep up the price they charge online retailers, and whether those retailers are in on the scam."