Trainee attached to a republic (4)
I believe the answer is:
cuba
'republic' is the definition.
(Cuba is an example)
'trainee attached to a' is the wordplay.
'trainee' becomes 'cub' (cub can mean a new recruit).
'attached to' says to put letters next to each other.
'cub'+'a'='CUBA'
(Other definitions for cuba that I've seen before include "West Indian island" , "Island S. of Florida" , "Island country involved in a 1962 missile crisis" , "Caribbean island republic" , "Castro's republic" .)