A neutral country in a particular war is a sovereign state which officially declares itself to be neutral towards the belligerents.
A sovereign state is, in international law, a nonphysical juridical entity that is represented by one centralised government that has sovereignty over a geographic area.
A belligerent is an individual, group, country, or other entity that acts in a hostile manner, such as engaging in combat.
Which Countries Are Neutral? by NowThis
A non-belligerent state does not need to be neutral.
A non-belligerent is a person, a state, or other organization that does not fight in a given conflict.
Sweden during World War 1 - Balancing Neutrality I THE ... by The Great War
The rights and duties of a neutral power are defined in Sections 5 and 13 of the Hague Convention of 1907.
A permanently neutral power is a sovereign state which is bound by international treaty to be neutral towards the belligerents of all future wars.
A treaty is an agreement under international law entered into by actors in international law, namely sovereign states and international organizations.
An example of a permanently neutral power is Switzerland.
The concept of neutrality in war is narrowly defined and puts specific constraints on the neutral party in return for the internationally recognised right to remain neutral.
Neutralism or a "neutralist policy" is a foreign policy position wherein a state intends to remain neutral in future wars.
Foreign Policy is an American news publication, founded in 1970 and focused on global affairs, current events, and domestic and international policy.
A sovereign state that reserves the right to become a belligerent if attacked by a party to the war is in a condition of armed neutrality.
Armed neutrality, in international politics, is the posture of a state or group of states that has no alliance with either side in a war, but asserts that it will defend itself against resulting incursions from any party.