Appear half-hearted, with silly behaviour in linguistic inquiry (9)
I believe the answer is:
semantics
'linguistic inquiry' is the definition.
The definition and answer can be both related to thinking as well as being singular nouns.
Perhaps there's an association between them I don't understand?
'appear half-hearted with silly behaviour' is the wordplay.
I cannot really see how this works, but
'behaviour' could be 'antics' (I have seen 'Amusing behaviour ' mean 'antics' so perhaps 'behaviour' could also mean 'antics') and 'antics' is located in the answer.
This explanation may well be incorrect...
'in' is the link.
Can you help me to learn more?
(Other definitions for semantics that I've seen before include "Main sects (anag.)" , "Meaning to study" , "The meaning attached to words" , "The significance of a text" , "Branch of linguistics concerned with meanings" .)