Where one will find Qataris party hard: answer _____ (4)
I believe the answer is:
doha
'where one will find qataris' is the definition.
(Doha is the capital of Qatar)
'party hard answer' is the wordplay.
'party' becomes 'do' (do is a kind of party).
'hard' becomes 'h' (abbreviation used in pencil classifications).
'answer' becomes 'a' (abbreviation eg in Q and A).
'do'+'h'+'a'='DOHA'
(Other definitions for doha that I've seen before include "Capital of Qatar" , "Trade round" , "Gulf resort" .)