Curious pelting rain? Get over it! (13)
I believe the answer is:
interrogative
'curious' is the definition.
(thesaurus)
'pelting rain? get over it' is the wordplay.
'pelting' indicates an anagram (letters hit or pelted).
'rain'+'get'+'over'+'it'='raingetoverit'
'raingetoverit' anagrammed gives 'INTERROGATIVE'.
(Other definitions for interrogative that I've seen before include "raising questions" , "Questioning" , "Denoting a question" .)