What is Neutral Property?

Legal Definition
Insurance. The words "neutral property " in a policy of insurance, have the effect of warranting that the property insured is neutral; that is, that it belongs to the citizens or subjects of a state in amity with the belligerent powers.

2. This neutrality must be complete hence the property of a citizen or subject of a neutral state, domiciled in the dominions of one of the belligerents, and carrying on commerce there, is not neutral property; for though such person continue to owe allegiance to bis country, and may at any time by returning there recover all the privileges of a citizen or subject of that country; yet while he resides in the dominion of a belligerent he contributes to the wealth and strength of such belligerent, and is not therefore entitled to the protection of a neutral flag; and his property is deemed enemy's property, and liable to capture, as such by the other belligerent. Marsh. Ins. B. 1, c. 9, s. 6; l John. Cas. 363; 3 Bos. & Pull. 207, u. 4; Esp. R. 108; l Caines' R. 60; 16 Johns. R. 128. See also 2 Johns. Cas. 478; 1 Caines' C. Err. xxv.; l Johns. Cas. 360; 2 Johns. Cas. 191.

3. If the warranty of neutrality be false at the time, it is made, the policy will be void ab initio. But if the 'ship, and property are neutral at the time when the risk commences, this is a sufficient compliance with a warranty of neutral property, and a subsequent declaration of war will not be a breach of it. Dougl. 705. See 1 Binn. 293; 8 Mass. 308; 14 Johns. R. 308; 5 Binn. 464; 2 Serg. & Rawle, 119; 4 Cranch, 185; 7 Cranch, 506; 2 Dall. 274.
-- Bouviers Law Dictionary
Legal Definition
Property which belongs to citizens of neutral powers, and is used, treated, and accompanied by proper insignia as such.
-- Black's Law Dictionary