Strong's G4754 — στρατεύομαι (verb)
strateuomai (strat-yoo'-om-ai) v.
1. to serve in a military campaign
2. (figuratively) to execute the apostolate (with its arduous duties and functions), to contend with carnal inclinations
[middle voice from the base of G4756]
KJV: soldier, (go to) war(-fare) 
Root(s): G4756 
Hebrew root: στρατία
Occurrences: 7