Boss's ruse in Windermere (8)
I believe the answer is:
employer
'boss's' is the definition.
(I've seen this before)
'ruse in windermere' is the wordplay.
'ruse' becomes 'ploy' (both can mean a trick or scheme).
'in' is an insertion indicator.
'windermere' becomes 'emer' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'ploy' placed into 'emer' is 'EMPLOYER'.
Can you help me to learn more?
(Other definitions for employer that I've seen before include "One paying staff" , "One engaging staff" , "Boss or proprietor" , "User; boss" , "One who engages workers" .)