From The Collaborative International Dictionary of English v.0.48 [gcide]:
Tremendous \Tre*men"dous\, a. [L. tremendus that is to be
trembled at, fearful, fr. tremere to tremble. See Tremble.]
Fitted to excite fear or terror; such as may astonish or
terrify by its magnitude, force, or violence; terrible;
dreadful; as, a tremendous wind; a tremendous shower; a
tremendous shock or fall.
[1913 Webster]
A tremendous mischief was a foot. --Motley.
[1913 Webster]
Syn: Terrible; dreadful; frightful; terrific; horrible;
awful.
[1913 Webster] -- Tre*men"dous*ly, adv. --
Tre*men"dous*ness, n.
[1913 Webster]
From WordNet (r) 3.0 (2006) [wn]:
tremendous
adj 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" [syn: enormous,
tremendous]
2: extraordinarily good or great ; 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" [syn: fantastic, grand,
{howling(a)}, marvelous, marvellous, {rattling(a)},
terrific, tremendous, wonderful, wondrous]
3: extreme in degree or extent or amount or impact; "in a
frightful hurry"; "spent a frightful amount of money" [syn:
frightful, terrible, awful, tremendous]