Check a Buddhist at regular intervals (5)
I believe the answer is:
audit
'check' is the definition.
(thesaurus)
'a buddhist at regular intervals' is the wordplay.
'at regular intervals' indicates alternate letters.
The alternate letters of 'buddhist' are 'udit'.
'a'+'udit'='AUDIT'
(Other definitions for audit that I've seen before include "Roman Aquae Sulis" , "Financial review" , "Inspection of a company's books" , "Inspection of records" , "review of books" .)