- shaking, shakiness, trembling, quiver, quivering, vibration, palpitation - a shaky motion; "the shaking of his fingers as he lit his pipe"
--1 is a kind of motion
--1 has particulars: tremolo; tremor - shakiness, ricketiness - the quality of being unstable and insecure; "the shakiness of the present regime"
--2 is a kind of instability, unstableness