It's scary to behave like Ofsted, dropping in on Bible study (7)
I believe the answer is:
spectre
'bible study' is the definition.
The definition and answer can be both related to thinking as well as being singular nouns.
Maybe you can see an association between them that I don't see?
'it's scary to behave like ofsted dropping in on' is the wordplay.
I cannot quite understand how this works, but
'on' could be 're' ('on' can be mean 'with reference to') and 're' is located in the answer.
'it' could be 't' (abbreviation. e.g. in 'tis) and 't' is present in the answer.
The remaining letters 'spec' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for spectre that I've seen before include "'Phantom, shade (7)'" , "something seen as a threat" , "Narrow ravine" , "Respect for a ghost" , "Ghost, phantom, apparition" .)