One's learned Queen must replace one American lady-in-waiting, for example (7)
I believe the answer is:
servant
'lady-in-waiting for example' is the definition.
(I know that lady-in-waiting is a type of servant)
'one's learned queen must replace one american' is the wordplay.
I cannot really understand how this works, but
'queen' could be 'ant' (queen is a type of ant) and 'ant' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for servant that I've seen before include "barmaid, for instance" , "Domestic - valet" , "Domestic help" , "Man" , "'Flunky, lackey (7)'" .)