Wise men in island country offering vision (11)
I believe the answer is:
imagination
'vision' is the definition.
(I know that vision can be written as imagination)
'wise men in island country' is the wordplay.
'wise men' becomes 'magi' (the three wise men from the nativity).
'in' indicates putting letters inside.
'island' becomes 'i'.
'country' becomes 'nation' (synonyms).
'i'+'nation'='ination'
'magi' going inside 'ination' is 'IMAGINATION'.
'offering' acts as a link.
(Other definitions for imagination that I've seen before include "Creativeness" , "vision" , "Power of mental invention" , "Fancy" , "Creative faculty" .)