Basically a level just above indestructible, usually applicable to a person/living entity. In general, dispite being indestructible, a fight between an indestructible being and an indefuckingstructible being will be won by the latter. Along with this title, there is a general implied awesomness of some sort, meriting the distinction over the lesser counter part, "indestructible".
"Wow, you'd think Bra'tac would have died by the tenth season, with all he's been through, but no, I suppose he's just indefuckingstructible"
by The Funkler September 17, 2009