The vacuous politician's overdue blueprint (8)
I believe the answer is:
template
'blueprint' is the definition.
The answer and definition can be both related to thinking as well as being singular nouns.
Perhaps there's a link between them I don't understand?
'the vacuous politician's overdue' is the wordplay.
'vacuous' says to hollow out the word (remove centre letters).
'politician' becomes 'MP' (Member of Parliament).
'overdue' becomes 'late' (similar in meaning).
'the' with its centre taken out is 'te'.
'te'+'mp'+'late'='TEMPLATE'
Can you help me to learn more?
(Other definitions for template that I've seen before include "original design" , "Pattern for document etc" , "Design model" , "Shape serving as model" , "Pattern for cutting out shapes" .)