Shaking woman getting key share (9)
I believe the answer is:
vibration
'shaking' is the definition.
(I know that shaking can be written as vibration)
'woman getting key share' is the wordplay.
'woman' becomes 'Vi' (short for Violet).
'getting' is a charade indicator (letters next to each other).
'key' becomes 'b' (eg B major, musical key).
'share' becomes 'ration' (a ration is a share of a limited resource).
'vi'+'b'+'ration'='VIBRATION'
(Other definitions for vibration that I've seen before include "fast pulse?" , "Oscillating movement" , "Palpitation, oscillation" , "Pulsation" , "Quick back and forward movement" .)