The story
- Proto-Indo-European*pós
- Proto-Indo-European*pósti
- Proto-Italic*posti
- Old Latinposte
- Latinpost
- Englishpost-
- Proto-Indo-European*wers-
- Proto-Germanic*werzaną
- Proto-West Germanic*werʀan
- Frankish*werʀ
- Early Medieval Latinwerra
- Old Northern Frenchguerre
- Old Englishwerre
- Middle Englishwerre
- Englishwar
- English todaypostwar
Etymology from Wiktionary, CC BY-SA 4.0.