tremble


tremble (http://definr.com/tremble)

     n : reflex shaking caused by cold or fear or excitement [syn: shiver,
          shake]
     v 1: move with or as if with a tremor; "his hands shook"; "My
          legs trembled when I went onstage" [syn: shake, didder]
     2: move or jerk quickly and involuntarily up and down or
        sideways; "His hands were trembling when he signed the
        document"