So turned again and shot (4)
I believe the answer is:
ergo
'so' is the definition.
(synonyms)
'turned again and shot' is the wordplay.
'turned' shows that the letters should be reversed in order.
'again' becomes 're' (prefix meaning 'again').
'and' says to put letters next to each other.
'shot' becomes 'go' (both can mean an attempt).
're' written backwards gives 'er'.
'er'+'go'='ERGO'
(Other definitions for ergo that I've seen before include "Therefore - what a goer" , "'Cogito, ---- sum'" , "Thus" , "Therefore (Latin)" , "as a consequence" .)