endless (often used hyperbolically).
"we got bogged down in interminable discussions"
synonyms: (seemingly) endless, never-ending, unending, nonstop, everlasting, ceaseless, unceasing, incessant, constant, continual, uninterrupted, sustained;
** Origin **
late Middle English: from Old French, or from late Latin interminabilis, from in- ‘not’ + terminare (see terminate).
Should have had this one earlier!
There are a couple of movie review shows that I love and "The Movie Show" with David and Margaret is legendary (OK it's now known as "At The Movies" but even after more than 9 years it will always be the former to me).
interminably is used regularly by David, and he says it so articulatelly and (against the definition without hyperbole.
This week he was reviewing 'Ender's Game'.
"... it was surprisingly dull, it's was a bit like standing a room where someone is playing a video game where you're not actually taking part but you have to watch interminably this game being played and really it's a bit boring ..."