Stomach discharge to remain constant (5,4)

I believe the answer is:

stand fire

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'remain constant' is the definition.
I don't know anything about this answer so I cannot judge whether this works.

'stomach discharge' is the wordplay.
'stomach' becomes 'stand' (synonyms).
'discharge' becomes 'fire' (synonyms).
'stand'+'fire'='STAND FIRE'

'to' acts as a link.

Can you help me to learn more?

I've seen this clue in The Telegraph.

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