Thought chaps inflamed should enter river (9)

I believe the answer is:

mentality

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'thought' is the definition.
The definition and answer can be both related to thinking as well as being singular nouns.
Perhaps you can see a link between them that I don't see?

'chaps inflamed should enter river' is the wordplay.
'chaps' becomes 'men' (chap means a man).
'inflamed' becomes 'lit' (as in a lit fire).
'should enter' is an insertion indicator.
'river' becomes 'tay' (Scottish river).
'lit' placed within 'tay' is 'tality'.
'men'+'tality'='MENTALITY'

Can you help me to learn more?

(Other definitions for mentality that I've seen before include "See 7" , "Way of thinking" .)

I've seen this clue in The Telegraph.

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