Investor’s displeasure with switch of sides (5)
I believe the answer is:
angel
'investor's' is the definition.
(term for a financial backer of new businesses)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for angel that I've seen before include "Messenger of God" , "Heavenly body" , "Cloud resident?" , "somewhere on the Northern Line" , "Word linking cake and fish" .)