WordNet (r) 3.0 (2006):

pronto
    adv 1: in a punctual manner; "he did his homework promptly"
           [syn: promptly, readily, pronto]

Moby Thesaurus II by Grady Ward, 1.0:

61 Moby Thesaurus words for "pronto":
   PDQ, all at once, all together, apace, at a blow, at a stroke,
   at once, at one blow, at one jump, at one stroke, at one swoop,
   at one time, decisively, directly, expeditiously, flat-out,
   forthwith, full tilt, hastily, immediately, in a flash, in a hurry,
   in a jiff, in a jiffy, in a twink, in a twinkling, in no time,
   in nothing flat, in short order, instantaneously, instanter,
   instantly, lickety-split, now, on the instant, on the spot,
   per saltum, posthaste, pretty damned quick, promptly, quickly,
   rapidly, right away, right now, right off, simultaneously, smartly,
   speedily, straightaway, straightway, subito, summarily, swiftly,
   then and there, this minute, this very minute, tout de suite,
   uno saltu, with all speed, without delay, without further delay