Ace crippled in battle (7)
I believe the answer is:
alamein
'battle' is the definition.
(First and Second Battles of El Alamein in 1942)
'ace crippled in' is the wordplay.
'ace' becomes 'a'.
'crippled' becomes 'lame' (synonyms).
'a'+'lame'+'in'='ALAMEIN'
(Other definitions for alamein that I've seen before include "Site of WW2 battle in Egypt" , "Montgomery - Rommel battle" , "on the north coast of Egypt" , "World War II N. African battle" .)