The Collaborative International Dictionary of English v.0.48:

Intimidation \In*tim`i*da"tion\, n. [Cf. F. intimidation.]
   The act of making timid or fearful or of deterring by
   threats; the state of being intimidated; as, the voters were
   kept from the polls by intimidation.
   [1913 Webster]

         The king carried his measures in Parliament by
         intimidation.                            --Paley.
   [1913 Webster]

WordNet (r) 3.0 (2006):

intimidation
    n 1: the act of intimidating a weaker person to make them do
         something [syn: bullying, intimidation]
    2: the feeling of discouragement in the face of someone's
       superior fame or wealth or status etc.
    3: the feeling of being intimidated; being made to feel afraid
       or timid
    4: a communication that makes you afraid to try something [syn:
       determent, deterrence, intimidation]

Moby Thesaurus II by Grady Ward, 1.0:

66 Moby Thesaurus words for "intimidation":
   admonition, argumentum baculinum, bluff, bluster,
   bluster and bluff, blustering, boastfulness, bravado, browbeating,
   bulldozing, bullying, bustle, caution, cautioning, caveat,
   coercion, commination, cowing, demoralization, denunciation,
   determent, deterrence, duress, empty threat, expostulation,
   fanfaronade, flurry, fluster, foreboding, frightening,
   frightening off, fuss, hectoring, high pressure, idle threat,
   imminence, implied threat, menace, monition, pressure,
   promise of harm, psychological warfare, rant, remonstrance,
   rodomontade, side, splutter, sputter, strong-arm tactics, swagger,
   swashbucklery, sword of Damocles, talking out of, the big stick,
   the bludgeon, the club, the jackboot, the mailed fist,
   the strong arm, the sword, threat, threateningness, threatfulness,
   violence, war of nerves, warning