The Collaborative International Dictionary of English v.0.48:

Emotion \E*mo"tion\, n. [L. emovere, emotum, to remove, shake,
   stir up; e out + movere to move: cf. F. ['e]motion. See
   Move, and cf. Emmove.]
   A moving of the mind or soul; excitement of the feelings,
   whether pleasing or painful; disturbance or agitation of mind
   caused by a specific exciting cause and manifested by some
   sensible effect on the body.
   [1913 Webster]

         How different the emotions between departure and
         return!                                  --W. Irving.
   [1913 Webster]

         Some vague emotion of delight.           --Tennyson.

   Syn: Feeling; agitation; tremor; trepidation; perturbation;
        passion; excitement.

   Usage: Emotion, Feeling, Agitation. Feeling is the
          weaker term, and may be of the body or the mind.
          Emotion is of the mind alone, being the excited action
          of some inward susceptibility or feeling; as, an
          emotion of pity, terror, etc. Agitation may be bodily
          or mental, and usually arises in the latter case from
          a vehement struggle between contending desires or
          emotions. See Passion. "Agitations have but one
          character, viz., that of violence; emotions vary with
          the objects that awaken them. There are emotions
          either of tenderness or anger, either gentle or
          strong, either painful or pleasing." --Crabb.
          [1913 Webster]

WordNet (r) 3.0 (2006):

emotion
    n 1: any strong feeling

Moby Thesaurus II by Grady Ward, 1.0:

43 Moby Thesaurus words for "emotion":
   a high, affect, affection, affectivity, arousal, attitude,
   emotional charge, emotional shade, emotivity, excitability,
   excitedness, excitement, exhilaration, experience, feeling,
   feeling tone, foreboding, gut reaction, heartthrob, impression,
   manic state, mental attitude, opinion, passion, position, posture,
   presentiment, profound sense, psychology, reaction, response,
   responsiveness, sensation, sense, sensibility, sensitiveness,
   sensitivity, sentiment, stance, stimulation, susceptibilities,
   undercurrent, way of thinking



The Devil's Dictionary (1881-1906):

EMOTION, n.  A prostrating disease caused by a determination of the
heart to the head.  It is sometimes accompanied by a copious discharge
of hydrated chloride of sodium from the eyes.