A prig — Chloe, resolved to tour a group of islands (11)
I believe the answer is:
archipelago
'group of islands' is the definition.
(I've seen this before)
'a prig chloe resolved to tour a' is the wordplay.
'resolved' indicates an anagram.
'to tour' is an insertion indicator (to tour can mean to go around).
'a'+'prig'+'chloe'='aprigchloe'
'aprigchloe' with letters rearranged gives 'archipelgo'.
'archipelgo' placed around 'a' is 'ARCHIPELAGO'.
(Other definitions for archipelago that I've seen before include "the Aegean, originally" , "Cluster of islands" , "Fiji, perhaps" , "Extensive group of islands" , "watery domain" .)