Free nude in arrest, surprisingly (12)
I believe the answer is:
unrestrained
'free' is the definition.
('unrestrained' is associated in meaning with 'free')
'nude in arrest surprisingly' is the wordplay.
'surprisingly' is an anagram indicator.
'nude'+'in'+'arrest'='nudeinarrest'
'nudeinarrest' with letters rearranged gives 'UNRESTRAINED'.
(Other definitions for unrestrained that I've seen before include "Not held back" , "Unchecked" , "Not restricted" , "Wild" , "Frantic" .)