Warship
E2. Naval, defence and maritime law enforcementDefinition
State vessel under command of a commissioned officer manned by armed forces crew.
A warship is a ship belonging to the armed forces of a state, bearing the external marks of its nationality, under the command of a commissioned officer whose name appears in the appropriate service list, and crewed by a regular military complement. This is the definition in UNCLOS Article 29 (1982). Warships enjoy complete immunity from the jurisdiction of any state other than the flag state on the high seas (UNCLOS Article 95) and may not be arrested or inspected; they hold the right of innocent passage in the territorial sea.
Source: UNCLOS 1982, Article 29 (definition of warship); Article 95 (immunity on the high seas).