greenmail n[green (money) + -mail (as in blackmail )]
: the practice of buying enough of a company's stock to threaten a hostile takeover and reselling it to the company at a price above market value
: the money paid for such stock
Source: Merriam-Webster's Dictionary of Law ©1996. Merriam-Webster, Incorporated. Published under license with Merriam-Webster, Incorporated.