Some time during December 1st, one expects the second coming (9)
I believe the answer is:
adventist
'one expects the second coming' is the definition.
I can't judge whether this defines the answer.
'some time during december 1st' is the wordplay.
'some' means to look at the middle letters.
'time' becomes 'min' (short for minute).
'during' means one lot of letters goes inside another.
'december' becomes 'advent' (I can't explain this - if you can you should believe this answer much more).
'ast' becomes 'st'.
The central letter of 'min' is 'i'.
'advent'+'st'='adventst'
'i' going into 'adventst' is 'ADVENTIST'.
Can you help me to learn more?
(Other definitions for adventist that I've seen before include "Sectarian" , "who looks for golden age?" , "member of cult" .)