Craven cold war moves by Yankee (8)
I believe the answer is:
cowardly
'craven' is the definition.
(synonyms)
'cold war moves by yankee' is the wordplay.
'moves' indicates an anagram.
'by' means one lot of letters go next to another.
'yankee' becomes 'Y' (phonetic alphabet: alpha, bravo, charlie etc.).
'cold'+'war'='coldwar'
'coldwar' is an anagram of 'cowardl'.
'cowardl'+'y'='COWARDLY'
(Other definitions for cowardly that I've seen before include "Lacking courage" , "chicken" , "Faint-hearted" , "Yellow" , "Lily-livered" .)