Father-in-law Jack's term for son-in-law Gaylord "Greg" Focker in the new "Little Fockers" movie starring Ben Stiller and Robert DeNiro.
Jack's use of the term stems from his realization that Greg, who now has 5-year old twins with his daughter Pam, is next in line to be the Byrnes-Focker family patriarch.
It is said of the situation where a person has the bad luck to make contact with his testicles against an undefined surface or object, intentioned or not.
Given the nature of the word, it is more appropriate to design cases where the interaction is made with a moving object, for example, a ball.
Although it is extremely painful for the victim, it tends to be considerably funny to people who witness it.
Today in the baseball game the pitcher took a nutshot; the baseball hit him in the nuts.
Man, I just watched the funniest nutshot video ever.