Completely rip while crying (9)

I believe the answer is:

tearfully

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

'rip while crying' is the wordplay.
'rip' becomes 'tear' (synonyms).
'while crying' becomes 'fully' (I can't explain this - if you can you should give a lot more credence to this answer).
'tear'+'fully'='TEARFULLY'

Can you help me to learn more?

I've seen this clue in The Irish Independent.

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