Nation has terrible rain (4)
I believe the answer is:
iran
'nation' is the definition.
(Iran is an example)
'terrible rain' is the wordplay.
'terrible' indicates anagramming the letters.
'rain' is an anagram of 'IRAN'.
'has' acts as a link.
(Other definitions for iran that I've seen before include "Persia some time ago" , "Rain (anag) - country" , "Iraq's neighbour" , "Country lying to south of Caspian sea" , "Tehran's country" .)