Want the world after the end of the world (6)
I believe the answer is:
dearth
'want' is the definition.
(dearth is a kind of want)
'the world after the end of the world' is the wordplay.
'the world' becomes 'earth' ('Earth' can be a synonym of 'world').
'after' is a charade indicator (letters next to each other).
'the end of' indicates one should take the final letters.
The last letter of 'world' is 'd'.
'earth' put after 'd' is 'DEARTH'.
(Other definitions for dearth that I've seen before include "Red hat for scarcity" , "deficiency" , "From shortage of food" , "Shortage, paucity" , "poverty" .)