Magazine rejected hotel -- a case of rancid fish (8)
I believe the answer is:
pilchard
'fish' is the definition.
(pilchard is a kind of fish)
'magazine rejected hotel a case of rancid' is the wordplay.
'magazine' becomes 'clip' ('clip' can be a synonym of 'magazine'**).
'rejected' says the letters should be written in reverse.
'hotel' becomes 'h' (phonetic alphabet: alpha, bravo, charlie etc.).
'case of' means to remove the middle letters (outsides of).
'rancid' with its centre taken out is 'rd'.
'clip' written backwards gives 'pilc'.
'pilc'+'h'+'a'+'rd'='PILCHARD'
(Other definitions for pilchard that I've seen before include "Fish of herring family" , "Small sea fish related to the herring" , "Small fatty fish, usually tinned" , "Small marine food fish" , "'Small fatty fish, usually canned (8)'" .)