Shaky over Sun being lively? (7)
I believe the answer is:
nervous
'shaky' is the definition.
(thesaurus)
'over sun being lively?' is the wordplay.
'being lively?' indicates an anagram (letters get livened up or moved around).
'over'+'sun'='oversun'
'oversun' is an anagram of 'NERVOUS'.
(Other definitions for nervous that I've seen before include "Frightened" , "On edge, anxious" , "Easily agitated, timid" , "'Apprehensive, uneasy (7)'" , "Twitchy" .)