Since going to prison, is shaky (5)
I believe the answer is:
aspen
'shaky' is the definition.
(thesaurus)
'since going to prison' is the wordplay.
'since' becomes 'as' (I've seen this in other clues).
'going to' means one lot of letters go next to another.
'prison' becomes 'pen' (I've seen this before).
'as'+'pen'='ASPEN'
'is' acts as a link.
(Other definitions for aspen that I've seen before include "ski resort in America?" , "somewhere in Colorado" , "Tremulous poplar" , "quill-like?" , "city in Colorado" .)