1. extraordinarily large in size or extent or amount or power or degree;
"an enormous boulder""enormous expenses""tremendous sweeping plains""a tremendous fact in human experience; that a whole civilization should be dependent on technology"- Walter Lippman"a plane took off with a tremendous noise"
2. extraordinarily good; used especially as intensifiers;
"a fantastic trip to the Orient""the film was fantastic!""a howling success""a marvelous collection of rare books""had a rattling conversation about politics""a tremendous achievement"