Never written out? (8)

I believe the answer is:

unpenned

I'm a little stuck... Click here to teach me more about this clue!

'out?' is the definition.
Both the answer and definition are verbs in their base form.
Perhaps there's an association between them I don't understand?

'never written' is the wordplay.
'never' becomes 'un' (I can't justify this - if you can you should believe this answer much more).
'written' becomes 'penned' (written with a pen).
'un'+'penned'='UNPENNED'

Can you help me to learn more?

I've seen this clue in The Times.

Want a hint initially instead of a full solution? Install my app