Faineance is a vice of deficit related to the corresponding virtue of Aspiration. It is a bit different from Stagnation, in that it is not just about physical sloth or laziness, inability to "get off the couch," but rather, a kind of "mental laziness."
Marriage and commitment have a way of forcing us to reconsider our long-held goals, sometimes to align them better to the needs of a partner, but sometimes to a fault, forsaking them for the wrong person.
From Aristotle's Golden Mean, we learn that every Virtue such as this also has two Vices. In the case of aspiration, the vice of excess is ambition that has Hubris, and the deficit is one of Faineance, or the "mental laziness" of just wondering around aimlessly with no goals, no curiosity of true interest in actually reaching a goal, like "wishful thinking" without intention. Hubris of course is filled with pathological narcissism causing relationships to fail by doing harm to the other partner, and Faineance carries a passive narcissism that harms the life of the partner who has it, and therefore harms the relationship indirectly, by non-contribution.
Many couples have fallen apart in partnership and intellectual attraction, simply because one or the other partner did not have aspirations.