Taken in by bulky catalogue, head of authority who's resigned (8)
I believe the answer is:
fatalist
'resigned' is the definition.
(I've seen this before)
'taken in by bulky catalogue head of authority' is the wordplay.
'taken in by' means one lot of letters goes inside another.
'bulky' becomes 'fat' (I can't explain this - if you can you should believe this answer much more).
'catalogue' becomes 'list' (a catalogue is a list of items).
'head of' indicates taking the first letters.
The initial letter of 'authority' is 'a'.
'fat'+'list'='fatlist'
'fatlist' placed around 'a' is 'FATALIST'.
'who's' is the link.
Can you help me to learn more?
(Other definitions for fatalist that I've seen before include "Predestinarian" , "philosophical type" , "One submitting to destiny" , "resigned" , "Person who accepts life as it comes" .)