Letters secure cricket ground (9)
I believe the answer is:
landlords
'letters' is the definition.
(people who let property)
'secure cricket ground' is the wordplay.
'secure' becomes 'land' (land can mean to secure or obtain).
'cricket ground' becomes 'lords' (English cricket ground).
'land'+'lords'='LANDLORDS'
(Other definitions for landlords that I've seen before include "People in pubs" , "They lease out properties" , "maybe posted locally?" , "letters" .)