Crossword Genius

Unorthodox scriptures, repeatedly exposed, increase suddenly (6)

Ross

I believe the answer is:

irrupt

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

'unorthodox scriptures repeatedly exposed' is the definition.
I can't tell whether this defines the answer.

'increase suddenly' is the wordplay.
I cannot quite see how this works, but
'increase' could be 'up' (upping is a kind of increasing) and 'up' is found within the answer.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?

(Other definitions for irrupt that I've seen before include "Enter forcibly or violently" , "Enter forcibly and suddenly" , "Break, rush, in" .)

I've seen this clue in The Independent.
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