Work in the surgery yet Dr isn't involved (9)
I believe the answer is:
dentistry
'work in the surgery' is the definition.
The answer and definition can be both related to thinking as well as being singular nouns.
Perhaps you can see a link between them that I can't see?
'yet dr isn't involved' is the wordplay.
'involved' indicates an anagram (involved can mean confusing or complex).
'yet'+'dr'+'isnt'='yetdrisnt'
'yetdrisnt' is an anagram of 'DENTISTRY'.
Can you help me to learn more?
(Other definitions for dentistry that I've seen before include "Work which is looking down in the mouth?" , "It's trendy in profession of teeth-care" , "Medical discipline" , "The profession of teeth care" , "Professional care of teeth" .)