Conscious of a battle to the east (5)
I believe the answer is:
aware
'conscious of' is the definition.
(being conscious means being aware of something)
'a battle to the east' is the wordplay.
'battle' becomes 'war' (armed conflict).
'to the east' becomes 'E' (abbreviation).
'a'+'war'+'e'='AWARE'
(Other definitions for aware that I've seen before include "Having knowledge (of fact)" , "fly" , "Acquainted with or conscious of" , "Having knowledge of, informed" , "Conscious, knowing about" .)