nom de guerre       
noun [ C ] uk/ˌnɒm.dəˈɡeər/ us/ˌnɑːm.dəˈɡer/  noms de guerre
 化名
a name chosen by someone to use when he or she is involved in a particular activity, especially fighting in a war
  Pol Pot was not his real name, but a nom de guerre adopted in the 1970s. 波尔布特不是他的真名,而是他在1970年代用的化名。