The Collaborative International Dictionary of English v.0.48:

Ulterior \Ul*te"ri*or\, a. [L., comp. of ultra, ultro, beyond,
   on the other side, properly cases of an old adjective, formed
   with a comparative suffix, which is akin to OL. uls beyond,
   L. olim formerly, hereafter, orig., at that time, ille that,
   OL. olle, ollus. Cf. Outrage.]
   1. Situated beyond, or on the farther side; thither; --
      correlative with hither.
      [1913 Webster]

   2. Further; remoter; more distant; succeeding; as, ulterior
      demands or propositions; ulterior views; what ulterior
      measures will be adopted is uncertain.
      [1913 Webster]

   Ulterior motive, Ulterior object or Ulterior aim, a
      motive, object or aim beyond that which is avowed.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Ulterior \Ul*te"ri*or\, n.
   Ulterior side or part. [R.] --Coleridge.
   [1913 Webster]

WordNet (r) 3.0 (2006):

ulterior
    adj 1: lying beyond what is openly revealed or avowed
           (especially being kept in the background or deliberately
           concealed); "subterranean motives for murder"; "looked
           too closely for an ulterior purpose in all knowledge"-
           Bertrand Russell [syn: subterranean, subterraneous,
           ulterior]
    2: beyond or outside an area of immediate interest; remote; "a
       suggestion ulterior to the present discussion";
       "without...any purpose, immediate or ulterior"- G.B.Shaw
    3: coming at a subsequent time or stage; "without ulterior
       argument"; "the mood posterior to" [syn: later(a),
       ulterior, posterior]

Moby Thesaurus II by Grady Ward, 1.0:

99 Moby Thesaurus words for "ulterior":
   accessory, additional, alien, ambiguous, ancillary, another,
   arcane, auxiliary, barbarian, barbaric, barbarous, beyond, buried,
   cabalistic, censored, classified, close, closed, collateral,
   concealed, contributory, covert, cryptic, dark, enigmatic,
   equivocal, esoteric, exotic, exterior, external, extra, extraneous,
   extraterrestrial, extrinsic, farther, foreign, foreign-born, fresh,
   further, guarded, hermetic, hidden, hush-hush, intrusive, latent,
   more, more distant, mysterious, new, obscure, obscured, occult,
   other, outland, outlandish, outside, personal, plus, private,
   privy, remote, remoter, restricted, secret, shrouded, smothered,
   spare, stifled, strange, supernumerary, supplemental,
   supplementary, suppressed, surplus, surreptitious, thither,
   top secret, unbreatheable, under cover, under security,
   under wraps, underhanded, underlying, undisclosable, undisclosed,
   undivulgable, undivulged, unearthly, unexpressed, unrevealable,
   unrevealed, unspoken, untellable, untold, unutterable, unuttered,
   unwhisperable, yon, yonder