Like intellectual Negligence or physical Mercenary behavior, which are vices about burdening a partner with a kind of laziness, shunning duties through the use of the excuse, "I don't know how", Failty is a character "vice of deficit of Resilience". It is "without resolve" to the point of being "win/lose" or destructive to the goals of the relationship. It is built on the laziness and cowardice of a person who lacks skills, but also lacks the assertiveness to proceed toward a goal.
In being unjust as a partner at contributing to achieve a goal, the failty in a lame or weak partner is only pretending to have real, true interest and collaboration toward a goal. Instead, only pretending, allowing the other partner to do all the diligent and disciplined work.
The partner with Failty uses an Immature Ego Defense, called, "Denial" - placing your hand in the cookie jar and then claiming that you weren't eating a cookie (The Ego Defenses guide us in finding friends and mates who happen to have similar maturity levels.)
It is pathologically narcissistic to have Failty, because we usually want to be its mature version, while Resilience, makes for "win/win" behavior in the face of a truly uncertain decision.
The other vice of Resilience as a virtue, is that of moral deficit, called, "Capriciousness", where a person vacillates between choices that all seem as valuable to the other. In the case of Failty, the respect and honor of a job well done is not made, and the partner doing all the work, then feels, doubly violated.
Someone who is romantically making use of Failty is a narcissist, wastefully taking resources (especially time and energy) away from the achievement of goals and the dreams of a mate, by pretending to have Resilience at a task that actually takes some discipline and effort that really will lead to success.
As a vice which makes partnership within relationships fail to get to goals, Failty is intellectually unattractive, consider cowardly behavior to be negative in many ways, including in sexual attraction, since it actually depletes the reserves of one's own, or the other partner's masculinity or femininity."