Something lacking in brief season in America (9)
I believe the answer is:
shortfall
'something lacking' is the definition.
I can't tell whether this definition defines the answer.
'brief season in america' is the wordplay.
'brief' becomes 'short' (synonyms).
'season in america' becomes 'fall' (US name for autumn).
'short'+'fall'='SHORTFALL'
'in' is the link.
Can you help me to learn more?
(Other definitions for shortfall that I've seen before include "lack" , "what we're lacking" , "Not quite what's expected" , "Deficit of something required" , "Loss" .)