A rare win involved Wellingtons (8)
I believe the answer is:
rainwear
'a rare win involved wellingtons' is the definition.
I can't tell whether this defines the answer.
'a rare win involved' is the wordplay.
'involved' indicates anagramming the letters (involved can mean confusing or complex).
'a'+'rare'+'win'='ararewin'
'ararewin' anagrammed gives 'RAINWEAR'.
Can you help me to learn more?
(Other definitions for rainwear that I've seen before include "Waterproof clothing" , "Coats" , "Waterproof clothes" , "This should keep him dry" , "Gear for wet weather" .)