Shake spoilt child in struggle (7)
I believe the answer is:
vibrate
'shake' is the definition.
(thesaurus)
'spoilt child in struggle' is the wordplay.
'spoilt child' becomes 'brat' (I've seen this before).
'in' indicates putting letters inside.
'struggle' becomes 'vie' (I've seen this before).
'brat' placed inside 'vie' is 'VIBRATE'.
(Other definitions for vibrate that I've seen before include "Quiver rapidly, resonate" , "Oscillate rapidly" , "Shake, quiver, or throb" , "tremble" , "Move rapidly to and fro" .)