quivering
     adj : vibrating slightly and irregularly; as e.g. with fear or
           cold or like the leaves of an aspen in a breeze; "a
           quaking bog"; "the quaking child asked for more";
           "quivering leaves of a poplar tree"; "with shaking
           knees"; "seemed shaky on her feet"; "sparkling light
           from the shivering crystals of the chandelier";
           "trembling hands" [syn: {quaking}, {shaking}, {shaky},
           {shivering}, {trembling}]
     n 1: a shaky motion; "the shaking of his fingers as he lit his
          pipe" [syn: {shaking}, {shakiness}, {trembling}, {quiver},
           {vibration}, {palpitation}]
     2: the act of vibrating [syn: {vibration}, {quiver}]
Source: WordNet® 2.0