Yield to witless underwriter's stupidity (9)
I believe the answer is:
surrender
This clue could be a double definition.
'yield' is the first definition.
(yield can mean to give up or surrender)
'witless underwriter's stupidity' is the second definition.
The answer and definition can be both acts as well as being singular nouns.
Perhaps there's a link between them I don't understand?
'to' acts as a link.
Can you help me to learn more?
(Other definitions for surrender that I've seen before include "Cease resistance" , "Yield to the control of another" , "Cede" , "Capitulate, relinquish" , "Submit (to an opponent)" .)