That twit Thomas is rash (9)

I believe the answer is:

foolhardy

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'is rash' is the definition.
(synonyms)

'that twit thomas' is the wordplay.
'that twit' becomes 'fool' (I've seen this before).
'thomas' becomes 'hardy' (I can't justify this - if you can you should believe this answer much more).
'fool'+'hardy'='FOOLHARDY'

Can you help me to learn more?

(Other definitions for foolhardy that I've seen before include "Hot-headed" , "Impulsive" , "Rash - incautious" , "Bold" , "Reckless" .)

I've seen this clue in the Evening Standard.

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