Act it out in the loft (5)
I believe the answer is:
attic
'loft' is the definition.
(synonyms)
'act it out' is the wordplay.
'out' indicates anagramming the letters (out can mean wrong or inaccurate).
'act'+'it'='actit'
'actit' is an anagram of 'ATTIC'.
'in the' is the link.
(Other definitions for attic that I've seen before include "Upper chamber" , "of Greek region" , "High level of" , "Loft room" , "room with lots of junk?" .)