Considering Henry VIII? Hardly (8)

I believe the answer is:

thinking

I'm a little stuck... Click here to teach me more about this clue!

'viii? hardly' is the definition.
I can't tell whether this defines the answer.

'considering henry' is the wordplay.
'considering' becomes 'thin' (I can't explain this - if you can you should give a lot more credence to this answer).
'henry' becomes 'king' (Henry VIII etc).
'thin'+'king'='THINKING'

Can you help me to learn more?

(Other definitions for thinking that I've seen before include "consideration" , "Mental process" , "Fancying" , "Reasoning in the mind" , "Thought" .)

I've seen this clue in the Sydney Morning Herald.

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