Good-sized building site (4)
I believe the answer is:
acre
'good-sized building site' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for acre that I've seen before include "Crusaders battlefield, now in Israel" , "0.405 of a hectare" , "Middle East port" , "Israeli seaport" , "marine location in Israel" .)