Promisecuity
The constant reneging or breaking of promises
The recent rash of promisecuity among close friends makes for no wonder that trust is hard to cultivate and keep.
promisecuous
Denotes the status of frequently making an verbal commitment to spread your legs as "collateral" for a favor that someone else does for you, such as loaning you money, giving you a ride, performing manual labor for you, etc.
Agreeing to help a promisecuous lady may be all well and good, but one should consider how likely it is that said chick will actually keep her word when the time comes for her to "deliver the goods".
Promisecuity
Promising over and over what it is impossible to promise.
Promisecuity was his worst defect of character.