I'd return in order to be a trespasser (8)
I believe the answer is:
intruder
'a trespasser' is the definition.
(I know that trespasser can be written as intruder)
'i'd return in order' is the wordplay.
'in order' indicates an anagram (the letters in a new order).
'id'+'return'='idreturn'
'idreturn' is an anagram of 'INTRUDER'.
'to be' is the link.
(Other definitions for intruder that I've seen before include "Unwanted visitor" , "Unwelcome guest" , "Trespasser" , "One entering uninvited" , "Uninvited person like burglar" .)