Corporate Law Looking for legal term

[bleong]

What is the legal word or term used to describe actions of one party who enters into a "partnership" 50/50 and obtained all the pertinent information and for lack of a written agreement and the US Government's new rule that says all such information contained in an application is not subject to FOIA. 2 wks later party one dumps the second party. It is not deliberate deception, bad faith, collusion, confidence, swindle but a term I heard but did not write down. I looked through many legal dictionaries and could ot find the word or terms? Any assistance is welcomed. Bill L.