The Collaborative International Dictionary of English v.0.48:

Imminence \Im"mi*nence\, n. [Cf. F. imminence, L. imminentia,
   See Imminent.]
   1. The condition or quality of being imminent; a threatening,
      as of something about to happen. The imminence of any
      danger or distress. --Fuller.
      [1913 Webster]

   2. That which is imminent; impending evil or danger. "But
      dare all imminence." --Shak.
      [1913 Webster]

WordNet (r) 3.0 (2006):

imminence
    n 1: the state of being imminent and liable to happen soon [syn:
         imminence, imminency, imminentness, impendence,
         impendency, forthcomingness]

Moby Thesaurus II by Grady Ward, 1.0:

77 Moby Thesaurus words for "imminence":
   access, accession, advance, advent, afflux, affluxion, aftertime,
   afteryears, anticipation, approach, approaching, appropinquation,
   approximation, appulse, bulldozing, by-and-by, certainty, coming,
   coming near, coming toward, commination, confidence, contemplation,
   course ahead, crystal ball, denunciation, determinism,
   distant future, empty threat, eventuality, expectancy, expectation,
   flowing toward, foreboding, foresight, forthcoming, forward look,
   future, future tense, futurism, futurity, hereafter, idle threat,
   immediate future, immediate prospect, implied threat, intimidation,
   menace, near future, nearing, nearness, offing, oncoming, outlook,
   posteriority, prediction, probability, project, promise of harm,
   prophecy, prospect, proximation, reliance, sword of Damocles,
   the future, the morrow, the sweet by-and-by, thought, threat,
   threateningness, threatfulness, time ahead, time just ahead,
   time to come, tomorrow, unastonishment, warning