Returning trespasser caught crossing land (5)
I believe the answer is:
acres
'land' is the definition.
(synonyms)
'returning trespasser caught crossing' is the wordplay.
'returning' is a reversal indicator.
'crossing' indicates the answer is hidden within the clue (the clue crosses over the answer).
'serca' is hidden within 'trespasser caught'.
'serca' back-to-front is 'ACRES'.
(Other definitions for acres that I've seen before include "Land areas" , "fields?" , "Imperial units or measures of land" , "farmland maybe?" , "Units of area" .)