Close, near, nigh, nearby are comparable both as adjectives and as adverbs when they mean not far (as in place, time, or relationship) from the point, position, or relation that is indicated or understood.
Close (see also CLOSE adj 2) commonly implies so slight a difference that the two things (sometimes persons) under consideration may be said to be almost in contact if the difference is in distance or almost coincident if the difference is in time, to be of the immediate family if the difference is in relationship, or to be very like the original if the difference is in a copy.
Near may often be used in place of close, but it carries a much less explicit suggestion of contiguousness or adjacency and may be used of persons or things that, though not far off (as in place, time, or relationship) are not almost in contact, almost coincident, or of the immediate family.
Near also is applied to things reproduced (as by copying, imitating, or translating) that more or less closely resemble but are far from replicas of the original; in this sense the term is often used in depreciation.
Nigh is somewhat outmoded or poetic in the sense of near. As an adverb it, even more often than near, is followed by to, unto, about, on, upon.
As an adjective it differs little from near except in sometimes being given preference in the comparative and superlative degrees to nearer and nearest.
Nearby indicates a position near in distance or close at hand.