Clothing worn by knight on river — sweaters and things (8)
I believe the answer is:
knitwear
'sweaters and things' is the definition.
'clothing worn by knight on river' is the wordplay.
'clothing' becomes 'kit' (I've seen this in other clues).
'worn by' indicates putting letters inside (I've seen this in other clues).
'knight' becomes 'n' (chess).
'on river' becomes 'wear' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'kit' going around 'n' is 'knit'.
'knit'+'wear'='KNITWEAR'
Can you help me to learn more?
(Other definitions for knitwear that I've seen before include "Jersey etc ..." , "that often covers blouses etc" , "Sweaters etc" , "Jumper" , "such as often goes over shirts and blouses" .)