It means one is apart, somehow (10)

I believe the answer is:

separation

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'it' is the definition.
The definition suggests a singular noun which matches the answer.

'one is apart somehow' is the wordplay.
'somehow' indicates anagramming the letters.
'one'+'is'+'apart'='oneisapart'
'oneisapart' is an anagram of 'SEPARATION'.

'means' is the link.

Can you help me to learn more?

(Other definitions for separation that I've seen before include "Split" , "Detachment" , "Break-up" , "Disunion" , "divorce" .)

I've seen this clue in The Irish Independent.

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