I see it counts as a TV trope:
This is a Fan Speak term used to describe any relationship that is obviously filled with Unresolved Sexual Tension but the characters resist going into a full blown relationship for a rather long time. Usually the two characters will be presented so that "they will" is the conclusion to root for; only rarely is the question of whether the writers think they should is in any real doubt....
"Will-they-won't-they" reminds me of "The Mock Turtle's Song": Will you, won't you, will you, won't you, will you join the dance?


