[syn: abrupt, precipitous, sharp]
The Collaborative International Dictionary of English v.0.48:
Precipitous \Pre*cip"i*tous\, a. [L. praeceps, -cipitis: cf. OF.
   precipiteux. See Precipice.]
   1. Steep, like a precipice; as, a precipitous cliff or
      mountain.
      [1913 Webster]
   2. Headlong; as, precipitous fall.
      [1913 Webster]
   3. Hasty; rash; quick; sudden; precipitate; as, precipitous
      attempts. --Sir T. Browne. "Marian's low, precipitous
      `Hush!'" --Mrs. Browning.
      [1913 Webster] -- Pre*cip"i*tous*ly, adv. --
      Pre*cip"i*tous*ness, n.
      [1913 Webster]
WordNet (r) 3.0 (2006):
precipitous
    adj 1: done with very great haste and without due deliberation;
           "hasty marriage seldom proveth well"- Shakespeare; "hasty
           makeshifts take the place of planning"- Arthur Geddes;
           "rejected what was regarded as an overhasty plan for
           reconversion"; "wondered whether they had been rather
           precipitate in deposing the king" [syn: hasty,
           overhasty, precipitate, precipitant, precipitous]
    2: extremely steep; "an abrupt canyon"; "the precipitous rapids
       of the upper river"; "the precipitous hills of Chinese
       paintings"; "a sharp drop" [syn: abrupt, precipitous,
       sharp]
Moby Thesaurus II by Grady Ward, 1.0:
66 Moby Thesaurus words for "precipitous":
   abrupt, accident-prone, acclivitous, arduous, bluff, bold,
   breakneck, breathless, careless, declivitous, desperate,
   devil-may-care, electrifying, furious, harum-scarum, hasty,
   headlong, hotheaded, hurried, impetuous, impulsive, mad,
   nerve-shattering, orthodiagonal, orthogonal, overeager,
   overenthusiastic, overzealous, panting, perpendicular, plumb,
   plunging, precipitant, precipitate, quick, rapid, rash, reckless,
   right-angle, right-angled, right-angular, rushing, sharp, sheer,
   shocking, sideling, slap-bang, slapdash, speedy, startling, steep,
   stickle, straight-up, straight-up-and-down, sudden, surprising,
   swift, unanticipated, unexpected, unforeseen, unlooked-for,
   unpredicted, up-and-down, vertical, wanton, wild