Wordnet 3.0
ADJECTIVE (1)
1. 
 existing or belonging to a time before a war; 
- Example: "prewar levels of industrial production"
WordNet (r) 3.0 (2006):
prewar
    adj 1: existing or belonging to a time before a war; "prewar
           levels of industrial production" [ant: postwar]
Moby Thesaurus II by Grady Ward, 1.0:
19 Moby Thesaurus words for "prewar":
   ante-bellum, antediluvian, antemundane, before the Fall,
   before the Flood, before the war, pre-Aryan, pre-Christian,
   pre-Renaissance, pre-Roman, preclassical, precultural, prehistoric,
   prelapsarian, premillenarian, premundane, prerevolutionary,
   preromantic, protohistoric