Of a person: living or dwelling nearest to one; happening to be nearest at a particular time. Now rare or merged in sense A. 2b.

Of a person, etc.: inclined to act as a neighbour; situated as a neighbour.

loosely. Neighbouring, situated in close proximity (though not in contact). †Of persons: Dwelling near.

That is next door; living next door; neighbouring, adjacent. Cf. next-door neighbour, n.