European nurse missing section to come into operation (5)

I believe the answer is:

enure

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'come into operation' is the definition.
I can't judge whether this defines the answer.

'european nurse missing section' is the wordplay.
'european' becomes 'e' (abbreviation e.g. EU).
'missing' suggests deleting specific letters.
'section' becomes 's' (legal abbreviation).
'nurse' with 's' removed is 'nure'.
'e'+'nure'='ENURE'

'to' is the link.

Can you help me to learn more?

(Another definition for enure that I've seen is " Practise".)

I've seen this clue in The Guardian.

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