Frightfully

Adverb

 * 1) In a frightful manner.
 * 2) Very, extremely.
 * It all went frightfully quickly.

Thesaurus
abominably, agonizingly, alarmingly, amazingly, appallingly, astoundingly, awfully, baldly, balefully, bitterly, blatantly, brashly, confoundedly, cruelly, damnably, deadly, deathly, deucedly, disconcertingly, dismayingly, distressingly, dolorously, dreadfully, egregiously, excessively, excruciatingly, exorbitantly, extravagantly, extremely, fearfully, flagrantly, forbiddingly, ghastly, grievously, gruesomely, hellishly, hideously, horrendously, horribly, horridly, horrifically, horrifyingly, improperly, inexcusably, infernally, inordinately, intolerably, lamentably, loathsomely, miserably, nakedly, offensively, openly, painfully, piteously, repugnantly, repulsively, revoltingly, sadly, shatteringly, shockingly, something awful, something fierce, sorely, staggeringly, startlingly, surprisingly, terribly, terrifically, torturously, tremendously, unashamedly, unbearably, unconscionably, unduly, unpardonably, very, woefully