Odd, exotic jewel, a fair attraction (6)
I believe the answer is:
dodgem
'a fair attraction' is the definition.
(dodgems are a fairground ride)
'odd exotic jewel' is the wordplay.
'exotic' is an anagram indicator (an unusual form of the letters).
'jewel' becomes 'gem' (synonyms).
'odd' is an anagram of 'dod'.
'dod'+'gem'='DODGEM'
(Other definitions for dodgem that I've seen before include "Electric car" , "Bumper car" , "Small car at funfair for bumping into others" , "Fairground amusement vehicle" , "Car used in fairground" .)