A credit expert's beginning to get the measure of land (4)
I believe the answer is:
acre
'the measure of land' is the definition.
(I've seen this before)
'a credit expert's beginning to' is the wordplay.
'credit' becomes 'cr'.
'beginning to' indicates taking the first letters.
The first letter of 'experts' is 'e'.
'a'+'cr'+'e'='ACRE'
'get' acts as a link.
(Other definitions for acre that I've seen before include "Unit of land measurement" , "Imperial land measurement" , "once occupied by Crusaders" , "stretch of land" , "4840 sq yds" .)