Occurs in spades after autumn (5)
I believe the answer is:
falls
'occurs' is the definition.
(falling is a kind of occuring)
'spades after autumn' is the wordplay.
'spades' becomes 's' (abbreviation in card games).
'after' means one lot of letters go next to another.
'autumn' becomes 'fall' ('fall' can be a synonym of 'autumn').
's' put after 'fall' is 'FALLS'.
'in' is the link.
(Other definitions for falls that I've seen before include "Drops" , "Victoria or Niagara, for example" , "American seasons" , "North Country force" , "Forces" .)