Yearning
Yearning is the deep, continuous longing beneath a character's specific goals — the human lack that the plot's wants are attempts to satisfy.
The novelist Robert Olen Butler puts yearning at the centre of character: fiction is not about the events, it is about human beings who yearn, and the events are what that yearning drives them into. A goal answers what does this character do next. A yearning answers why has this person been like this their whole life.
The practical difference from a want is duration. Wants are satisfiable and local — get the job, reach the border, win the argument. Yearnings do not resolve: to be forgiven, to be seen, to belong somewhere, to be safe, to matter to someone. A character can achieve every goal in the book and still be reaching, which is why the ending of a well-built story so often grants the want and leaves the yearning exposed.
It is also the fastest repair for a protagonist who is competent and uninteresting. Such characters usually have objectives and no longing, so nothing they do costs them anything internally. Name what the person has always been short of, and their choices start to carry weight — including the bad ones.
It surfaces in interiority more than in dialogue, because people state their goals and conceal their longings, often from themselves.