She's in diametric opposition! (4)
I believe the answer is:
maid
This might be a double definition.
'she's' is the first definition.
Both the definition and answer are singular nouns.
Maybe you can see an association between them that I can't see?
'diametric opposition' is the second definition.
The definition and answer can be both people as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'in' is the link.
Can you help me to learn more?
(Other definitions for maid that I've seen before include "- - -of-all-work" , "Young woman - servant" , "One in service" , "Serving girl" , "daughter?" .)