Hunter erected a place to sleep in (6)
I believe the answer is:
nimrod
'hunter' is the definition.
(I've seen this in another clue)
'erected a place to sleep in' is the wordplay.
'erected' shows that the letters should be reversed in order (in a down clue, letters go up).
'a place to sleep' becomes 'dorm' (short for dormitory).
'dorm'+'in'='dormin'
'dormin' backwards is 'NIMROD'.
(Other definitions for nimrod that I've seen before include "Mighty hunter of the Bible" , "Mighty Biblical ruler, said to have built Tower of Babel" , "Best-known of Elgar's Enigma Variations" , "Might hunter of Genesis" , "Dim Ron was a bad Biblical hunter" .)