At which time, novel about hotel gets rejected (4)
I believe the answer is:
when
'at which time' is the definition.
(I've seen this in another clue)
'novel about hotel gets rejected' is the wordplay.
'novel' becomes 'new' (synonyms).
'about' indicates putting letters inside.
'hotel' becomes 'h' (phonetic alphabet).
'gets rejected' says the letters should be written backwards.
'new' going around 'h' is 'nehw'.
'nehw' written backwards gives 'WHEN'.
(Other definitions for when that I've seen before include "At what time?" , "As soon as" , "Over what period?" , "Say it when you''ve had enough" , "stop pouring the drink" .)