Blokes gathered round island monument (7)
I believe the answer is:
obelisk
'monument' is the definition.
(type of monument or landmark)
'blokes gathered round island' is the wordplay.
'gathered' is an anagram indicator (the letters are gathered into a new order).
'round' is an insertion indicator.
'island' becomes 'i' (geographical abbreviation).
'blokes' with letters rearranged gives 'obelsk'.
'obelsk' enclosing 'i' is 'OBELISK'.
(Other definitions for obelisk that I've seen before include "Stone pillar tapering towards a point" , "Ancient Egyptian monument" , "Tapering monumental pillar" , "Tapering pillar erected as monument" , "Stone "needle"" .)