Adjective- a word like green, hungry, impossible, which is used when we
describe people, things, events etc.
In numerous fixed expressions, an adjective is placed immediately after the noun it governs:
Examples: attorney-general, body politic, court martial.
- These are to be distinguished from cases in which an adjective just
happens to follow the noun it governs
Adjectives are used in connection with nouns and pronouns.
Examples: a green apple; She's hungry.
In the sentence - Sir James Murray, the lexicographer, was born in Hawick.
- The second element, the lexicographer, is appositive to the
first, Sir James Murray.
Similarly- The highest mountain in New Zealand, Mount Cook, is called Aorangi by the Maoris.
- The second element, Mount Cook, is appositive to the first, The
highest mountain in New Zealand.
The appositive is not an adjective.
In both cases the second element syntactically duplicates the first. This is the most straightforward type of apposition
(Reference-Fowler's Modern English Usage)