Thanks court completely and with understanding (9)

I believe the answer is:

tactfully

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'with understanding' is the definition.
Both the answer and definition are adverbs. Maybe there's a link between them I don't understand?

'thanks court completely' is the wordplay.
'thanks' becomes 'ta' (UK informal version of 'thank you').
'court' becomes 'ct' (abbreviation used in road names).
'completely' becomes 'fully' (in full).
'ta'+'ct'+'fully'='TACTFULLY'

'and' is the link.

Can you help me to learn more?

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

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