Lack of understanding displayed by sovereign or ancestor (9)

I believe the answer is:

ignorance

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'lack of understanding' is the definition.
'ignorance' can be an answer for 'lack' (I have seen 'Lack of knowledge' mean 'ignorance' so perhaps 'lack' could also mean 'ignorance'). I am unsure of the 'of understanding' bit.

'displayed by sovereign or ancestor' is the wordplay.
'displayed by' indicates the answer is hidden within the clue.
'IGNORANCE' is hidden in the letters of 'sovereign or ancestor'.

Can you help me to learn more?

(Other definitions for ignorance that I've seen before include "Ken lacking" , "Groin acne (anag.)" , "being uninformed" , "in all innocence" , "Lack of knowledge" .)

I've seen this clue in The Independent.

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