Class lexicographer turned up in Caribbean island (8)
I believe the answer is:
category
'class' is the definition.
(synonyms)
'lexicographer turned up in caribbean island' is the wordplay.
'lexicographer' becomes 'roget' (I've seen this before).
'turned up' is a reversal indicator.
'in' is an insertion indicator.
'caribbean island' becomes 'cay' (type of topical island as found in the Caribbean).
'roget' written backwards gives 'tegor'.
'tegor' placed inside 'cay' is 'CATEGORY'.
(Other definitions for category that I've seen before include "Group of classified items" , "Classification of grey-coat" , "Class of grey-coat" , "Kind" , "Class or order" .)