Try to block some pain (5)
I believe the answer is:
agony
'pain' is the definition.
(agony is a kind of pain)
'try to block some' is the wordplay.
'try' becomes 'go' (both can mean an attempt).
'to block' is an insertion indicator (block can mean to fill a hole in something).
'some' becomes 'any' (similar in meaning).
'go' placed into 'any' is 'AGONY'.
(Other definitions for agony that I've seen before include "sort of aunt" , "Mental suffering" , "Distress" , "Extreme pain" , "Pain, torment" .)