Use a rosary (4)
I believe the answer is:
pray
'use a rosary' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for pray that I've seen before include "Earnestly ask (God?)" , "Beg" , "Wish earnestly (for a particular outcome)" , "Hope earnestly (for particular outcome)" , "follow religious practice" .)