Warning given by European after live conflict (6)
I believe the answer is:
beware
'warning' is the definition.
('beware!' might be shouted as a warning)
'by european after live conflict' is the wordplay.
'by' says to put letters next to each other.
'european' becomes 'E' (abbreviation e.g. EU).
'after' says to put letters next to each other.
'live' becomes 'be' (synonyms).
'conflict' becomes 'war' (war is a kind of conflict).
'be'+'war' is 'bewar'.
'e' after 'bewar' is 'BEWARE'.
'given' acts as a link.
(Other definitions for beware that I've seen before include "Steer clear of" , "See 18" , "Take heed" , "Archaic injunction to be careful, look out" , "Be alert for dangers" .)