Care about land measurement (4)
'land measurement' is the definition.
(I've seen this before)
'care about' is the wordplay.
'about' indicates anagramming the letters.
'care' with letters rearranged gives 'ACRE'.
(Other definitions for acre that I've seen before include "Unit of area of 4,840 square yards", "Area measure - Israeli port - Brazilian state", "Muslims here besieged", "Not a lot of land", "Crusaders battlefield, now in Israel".)