The Collaborative International Dictionary of English v.0.48:

Scary \Sca"ry\, n. [Prov. E. scare scraggy.]
   Barren land having only a thin coat of grass. [Prov. Eng.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Scary \Scar"y\, a. [From Scare.]
   1. Subject to sudden alarm. [Colloq. U. S.] --Whittier.
      [1913 Webster]

   2. Causing fright; alarming. [Colloq. U. S.]
      [1913 Webster]

WordNet (r) 3.0 (2006):

scary
    adj 1: provoking fear terror; "a scary movie"; "the most
           terrible and shuddery...tales of murder and revenge"
           [syn: chilling, scarey, scary, shivery,
           shuddery]

Moby Thesaurus II by Grady Ward, 1.0:

59 Moby Thesaurus words for "scary":
   aghast, alarming, anxious, awing, bashful, chilling, cowardly,
   crawly, creepy, daunting, deterrent, deterring, diffident,
   disconcerting, discouraging, disheartening, dismaying, disquieting,
   eerie, fear-inspiring, fearful, fearing, fearsome, frightened,
   frightening, frightful, goosy, hair-raising, horrendous, horrible,
   horrid, horrifying, in fear, intimidating, jumpy, mousy, nervous,
   overawing, rabbity, scared, scaring, shaky, shivery, shrinking,
   shy, skittery, skittish, spine-chilling, spooky, startling,
   startlish, terrified, terrifying, timid, timorous, trembling,
   tremulous, trepidant, trigger-happy