Lost leader held by state for murder (4)
I believe the answer is:
slay
'murder' is the definition.
(synonyms)
'lost leader held by state' is the wordplay.
'leader' indicates taking the first letters.
'held by' indicates putting letters inside.
'state' becomes 'say' (to state something is to say it).
The first letter of 'lost' is 'l'.
'l' placed within 'say' is 'SLAY'.
'for' acts as a link.
(Other definitions for slay that I've seen before include "Kill intentionally" , "Destroy" , "Kill (literary)" , "Kill with premeditation" , "Kill, murder" .)