term:

In Terrorem

in terrorem adv or adj

[Latin, so as to produce terror]
: by way of threat or intimidation
: serving or intended to threaten or intimidate [overbroad covenants not to compete which have in terrorem effect on employees "J. D. Calamari and J. M. Perillo"] NOTE: In terrorem is most commonly used to describe a condition in a will that threatens an heir with forfeiture if he or she challenges the validity of the will.

Source: Merriam-Webster's Dictionary of Law ©1996. Merriam-Webster, Incorporated. Published under license with Merriam-Webster, Incorporated.