throbbing

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

     adj : pounding or beating strongly or violently; "a throbbing
           pain"; "the throbbing engine of the boat"
     n 1: an instance of rapid strong pulsation (of the heart); "he
          felt a throbbing in his head" [syn: throb, pounding]
     2: a sound with a strong rhythmic beat; "the throbbing of the
        engines"