One thousand coming to an isle (3)
I believe the answer is:
man
'isle' is the definition.
(the Isle of Man is an example)
'one thousand coming to an' is the wordplay.
'one thousand' becomes 'm' (Roman numeral for a thousand).
'coming to' is a charade indicator (letters next to each other).
'm'+'an'='MAN'
(Other definitions for man that I've seen before include "us?" , "Individual" , "knight, perhaps?" , "Chap" , "Adult human male" .)