Synonyms for Marine (same or very similar meaning)
WordNet sense 1 (a member of the United States Marine Corps):
leatherneck, devil dog, shipboard soldierWordNet sense 2 (relating to or involving ships or shipping or navigation or seamen):
maritime, nauticalWordNet sense 3 (operating or living or growing in water):
aquaticFrom the ODE community, based on WordNetadd/edit